An oxidative decarboxylation process that converts GLUCOSE-6-PHOSPHATE to D-ribose-5-phosphate via 6-phosphogluconate. The pentose product is used in the biosynthesis of NUCLEIC ACIDS. The generated energy is stored in the form of NADPH. This pathway is prominent in tissues which are active in the synthesis of FATTY ACIDS and STEROIDS.
An enzyme of the transferase class that catalyzes the reaction sedoheptulose 7-phosphate and D-glyceraldehyde 3-phosphate to yield D-erythrose 4-phosphate and D-fructose phosphate in the PENTOSE PHOSPHATE PATHWAY. (Dorland, 27th ed) EC 2.2.1.2.
Pentosephosphates are monosaccharides, specifically pentoses, that have a phosphate group attached, playing crucial roles in carbohydrate metabolism, such as being intermediates in the pentose phosphate pathway and serving as precursors for nucleotide synthesis.
An enzyme of the transferase class that catalyzes the conversion of sedoheptulose 7-phosphate and D-glyceraldehyde 3-phosphate to D-ribose 5-phosphate and D-xylulose 5-phosphate in the PENTOSE PHOSPHATE PATHWAY. (Dorland, 27th ed) EC 2.2.1.1.
Glucose-6-Phosphate Dehydrogenase (G6PD) is an enzyme that plays a critical role in the pentose phosphate pathway, catalyzing the oxidation of glucose-6-phosphate to 6-phosphoglucono-δ-lactone while reducing nicotinamide adenine dinucleotide phosphate (NADP+) to nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), thereby protecting cells from oxidative damage and maintaining redox balance.
An enzyme of the oxidoreductase class that catalyzes the reaction 6-phospho-D-gluconate and NADP+ to yield D-ribulose 5-phosphate, carbon dioxide, and NADPH. The reaction is a step in the pentose phosphate pathway of glucose metabolism. (From Dorland, 27th ed) EC 1.1.1.43.
A vitamin antagonist which has teratogenic effects.
Ribulose substituted by one or more phosphoric acid moieties.
Ribose substituted in the 1-, 3-, or 5-position by a phosphoric acid moiety.
A metabolic process that converts GLUCOSE into two molecules of PYRUVIC ACID through a series of enzymatic reactions. Energy generated by this process is conserved in two molecules of ATP. Glycolysis is the universal catabolic pathway for glucose, free glucose, or glucose derived from complex CARBOHYDRATES, such as GLYCOGEN and STARCH.
An ester of glucose with phosphoric acid, made in the course of glucose metabolism by mammalian and other cells. It is a normal constituent of resting muscle and probably is in constant equilibrium with fructose-6-phosphate. (Stedman, 26th ed)
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
Inorganic salts of phosphoric acid.
Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed)
A series of oxidative reactions in the breakdown of acetyl units derived from GLUCOSE; FATTY ACIDS; or AMINO ACIDS by means of tricarboxylic acid intermediates. The end products are CARBON DIOXIDE, water, and energy in the form of phosphate bonds.
A pentose active in biological systems usually in its D-form.
'Sugar phosphates' are organic compounds that consist of a sugar molecule linked to one or more phosphate groups, playing crucial roles in biochemical processes such as energy transfer and nucleic acid metabolism.
Xylose is a monosaccharide, a type of sugar, that is commonly found in woody plants and fruits, and it is used in medical testing to assess the absorptive capacity of the small intestine.
Gluconates are salts or esters of gluconic acid, primarily used in medical treatments as a source of the essential nutrient, calcium, and as a chelating agent to bind and remove toxic metals such as aluminum and iron from the body.
A 5-carbon keto sugar.
Enzymes that catalyze the interconversion of aldose and ketose compounds.
A four-carbon sugar that is found in algae, fungi, and lichens. It is twice as sweet as sucrose and can be used as a coronary vasodilator.
An aldose-ketose isomerase that catalyzes the reversible interconversion of glucose 6-phosphate and fructose 6-phosphate. In prokaryotic and eukaryotic organisms it plays an essential role in glycolytic and gluconeogenic pathways. In mammalian systems the enzyme is found in the cytoplasm and as a secreted protein. This secreted form of glucose-6-phosphate isomerase has been referred to as autocrine motility factor or neuroleukin, and acts as a cytokine which binds to the AUTOCRINE MOTILITY FACTOR RECEPTOR. Deficiency of the enzyme in humans is an autosomal recessive trait, which results in CONGENITAL NONSPHEROCYTIC HEMOLYTIC ANEMIA.
A class of carbohydrates that contains five carbon atoms.
An aldotriose which is an important intermediate in glycolysis and in tryptophan biosynthesis.
Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.
A five-carbon sugar alcohol derived from XYLOSE by reduction of the carbonyl group. It is as sweet as sucrose and used as a noncariogenic sweetener.
A rod-shaped to ellipsoidal, gram-negative bacterium which oxidizes ethanol to acetic acid and prefers sugar-enriched environments. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
A nonmetallic element with atomic symbol C, atomic number 6, and atomic weight [12.0096; 12.0116]. It may occur as several different allotropes including DIAMOND; CHARCOAL; and GRAPHITE; and as SOOT from incompletely burned fuel.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
'Glucosephosphates' are organic compounds resulting from the reaction of glucose with phosphoric acid, playing crucial roles in various metabolic processes, such as energy transfer and storage within cells.
Enzymes that catalyze a reverse aldol condensation. A molecule containing a hydroxyl group and a carbonyl group is cleaved at a C-C bond to produce two smaller molecules (ALDEHYDES or KETONES). EC 4.1.2.
Hexosephosphates are sugar phosphate molecules, specifically those derived from hexoses (six-carbon sugars), such as glucose-6-phosphate and fructose-6-phosphate, which play crucial roles in various metabolic pathways including glycolysis, gluconeogenesis, and the pentose phosphate pathway.
Cellular processes in biosynthesis (anabolism) and degradation (catabolism) of CARBOHYDRATES.
Enzymes that catalyze the epimerization of chiral centers within carbohydrates or their derivatives. EC 5.1.3.
3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2- hydroxyethyl)-4-methylthiazolium chloride.
The key substance in the biosynthesis of histidine, tryptophan, and purine and pyrimidine nucleotides.
Allosteric enzymes that regulate glycolysis and gluconeogenesis. These enzymes catalyze phosphorylation of fructose-6-phosphate to either fructose-1,6-bisphosphate (PHOSPHOFRUCTOKINASE-1 reaction), or to fructose-2,6-bisphosphate (PHOSPHOFRUCTOKINASE-2 reaction).
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Arabinose is a simple, pentose sugar (a monosaccharide with five carbon atoms) that is a constituent of various polysaccharides and glycosides, particularly found in plant tissues and some microorganisms, and can be metabolized in humans as a source of energy through the pentose phosphate pathway.
Trioses are monosaccharides, specifically simple sugars, that contain three carbon atoms, and can be glyceraldehydes or dihydroxyacetones, which are important intermediates in metabolic pathways such as glycolysis.
Complex sets of enzymatic reactions connected to each other via their product and substrate metabolites.
Polyhydric alcohols having no more than one hydroxy group attached to each carbon atom. They are formed by the reduction of the carbonyl group of a sugar to a hydroxyl group.(From Dorland, 28th ed)
An enzyme that catalyzes the conversion of ATP and a D-hexose to ADP and a D-hexose 6-phosphate. D-Glucose, D-mannose, D-fructose, sorbitol, and D-glucosamine can act as acceptors; ITP and dATP can act as donors. The liver isoenzyme has sometimes been called glucokinase. (From Enzyme Nomenclature, 1992) EC 2.7.1.1.
Transferases are enzymes transferring a group, for example, the methyl group or a glycosyl group, from one compound (generally regarded as donor) to another compound (generally regarded as acceptor). The classification is based on the scheme "donor:acceptor group transferase". (Enzyme Nomenclature, 1992) EC 2.
Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.
A class of enzymes that catalyze geometric or structural changes within a molecule to form a single product. The reactions do not involve a net change in the concentrations of compounds other than the substrate and the product.(from Dorland, 28th ed) EC 5.
The dynamic collection of metabolites which represent a cell's or organism's net metabolic response to current conditions.
An enzyme that catalyzes the formation of phosphoribosyl pyrophosphate from ATP and ribose-5-phosphate. EC 2.7.6.1.
Self-replicating cytoplasmic organelles of plant and algal cells that contain pigments and may synthesize and accumulate various substances. PLASTID GENOMES are used in phylogenetic studies.
Heptoses are rare monosaccharides (simple sugars) containing seven carbon atoms, with a general formula of C7H14O7, which can exist in various structural forms such as D-glycero-D-manno-heptose and D-glycero-D-gulo-heptose.
An intermediate compound in the metabolism of carbohydrates, proteins, and fats. In thiamine deficiency, its oxidation is retarded and it accumulates in the tissues, especially in nervous structures. (From Stedman, 26th ed)
A disease-producing enzyme deficiency subject to many variants, some of which cause a deficiency of GLUCOSE-6-PHOSPHATE DEHYDROGENASE activity in erythrocytes, leading to hemolytic anemia.
Pyruvates, in the context of medical and biochemistry definitions, are molecules that result from the final step of glycolysis, containing a carboxylic acid group and an aldehyde group, playing a crucial role in cellular metabolism, including being converted into Acetyl-CoA to enter the Krebs cycle or lactate under anaerobic conditions.
Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.
The systematic identification and quantitation of all the metabolic products of a cell, tissue, organ, or organism under varying conditions. The METABOLOME of a cell or organism is a dynamic collection of metabolites which represent its net response to current conditions.
Hexoses are simple monosaccharides, specifically six-carbon sugars, which include glucose, fructose, and galactose, and play crucial roles in biological processes such as energy production and storage, and structural components of cells.
A major C19 steroid produced by the ADRENAL CORTEX. It is also produced in small quantities in the TESTIS and the OVARY. Dehydroepiandrosterone (DHEA) can be converted to TESTOSTERONE; ANDROSTENEDIONE; ESTRADIOL; and ESTRONE. Most of DHEA is sulfated (DEHYDROEPIANDROSTERONE SULFATE) before secretion.
Salts or esters of LACTIC ACID containing the general formula CH3CHOHCOOR.
Unstable isotopes of carbon that decay or disintegrate emitting radiation. C atoms with atomic weights 10, 11, and 14-16 are radioactive carbon isotopes.
Biosynthesis of GLUCOSE from nonhexose or non-carbohydrate precursors, such as LACTATE; PYRUVATE; ALANINE; and GLYCEROL.
A genus of asporogenous bacteria that is widely distributed in nature. Its organisms appear as straight to slightly curved rods and are known to be human and animal parasites and pathogens.
An allosteric enzyme that regulates glycolysis by catalyzing the transfer of a phosphate group from ATP to fructose-6-phosphate to yield fructose-1,6-bisphosphate. D-tagatose- 6-phosphate and sedoheptulose-7-phosphate also are acceptors. UTP, CTP, and ITP also are donors. In human phosphofructokinase-1, three types of subunits have been identified. They are PHOSPHOFRUCTOKINASE-1, MUSCLE TYPE; PHOSPHOFRUCTOKINASE-1, LIVER TYPE; and PHOSPHOFRUCTOKINASE-1, TYPE C; found in platelets, brain, and other tissues.
The rate dynamics in chemical or physical systems.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
A metabolite of TESTOSTERONE or ANDROSTENEDIONE with a 3-alpha-hydroxyl group and without the double bond. The 3-beta hydroxyl isomer is epiandrosterone.
ATP:pyruvate 2-O-phosphotransferase. A phosphotransferase that catalyzes reversibly the phosphorylation of pyruvate to phosphoenolpyruvate in the presence of ATP. It has four isozymes (L, R, M1, and M2). Deficiency of the enzyme results in hemolytic anemia. EC 2.7.1.40.
Animal form of fatty acid synthase which is encoded by a single gene and consists of seven catalytic domains and is functional as a homodimer. It is overexpressed in some NEOPLASMS and is a target in humans of some ANTINEOPLASTIC AGENTS and some ANTI-OBESITY AGENTS.
Enzymes that catalyze the dehydrogenation of GLYCERALDEHYDE 3-PHOSPHATE. Several types of glyceraldehyde-3-phosphate-dehydrogenase exist including phosphorylating and non-phosphorylating varieties and ones that transfer hydrogen to NADP and ones that transfer hydrogen to NAD.
A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.
A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)
Fructosephosphates are organic compounds resulting from the combination of fructose with a phosphate group, playing crucial roles in various metabolic processes, particularly within carbohydrate metabolism.
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Method for assessing flow through a system by injection of a known quantity of radionuclide into the system and monitoring its concentration over time at a specific point in the system. (From Dorland, 28th ed)
A group of enzymes that transfers a phosphate group onto an alcohol group acceptor. EC 2.7.1.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
A glucose dehydrogenase that catalyzes the oxidation of beta-D-glucose to form D-glucono-1,5-lactone, using NAD as well as NADP as a coenzyme.
Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc.
A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)
Adenine nucleotides are molecules that consist of an adenine base attached to a ribose sugar and one, two, or three phosphate groups, including adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP), which play crucial roles in energy transfer and signaling processes within cells.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
Glyoxylates are organic compounds that are intermediate products in the metabolic pathways responsible for the breakdown and synthesis of various molecules, including amino acids and carbohydrates, and are involved in several biochemical processes such as the glyoxylate cycle.
Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
An enzyme that catalyzes the conversion of (S)-malate and NAD+ to oxaloacetate and NADH. EC 1.1.1.37.
Total mass of all the organisms of a given type and/or in a given area. (From Concise Dictionary of Biology, 1990) It includes the yield of vegetative mass produced from any given crop.
Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.
A species of gram-positive, asporogenous, non-pathogenic, soil bacteria that produces GLUTAMIC ACID.
The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Catalyzes the oxidation of GLUTATHIONE to GLUTATHIONE DISULFIDE in the presence of NADP+. Deficiency in the enzyme is associated with HEMOLYTIC ANEMIA. Formerly listed as EC 1.6.4.2.
The five-carbon building blocks of TERPENES that derive from MEVALONIC ACID or deoxyxylulose phosphate.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
Glycogen is a multibranched polysaccharide of glucose serving as the primary form of energy storage in animals, fungi, and bacteria, stored mainly in liver and muscle tissues. (Two sentences combined as per your request)
Life or metabolic reactions occurring in an environment containing oxygen.
A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, and sweetening agent.
Trehalose is a non-reducing disaccharide composed of two glucose molecules linked by an alpha, alpha-1,1-glycosidic bond, naturally found in some plants and microorganisms, serving as a cryoprotectant and providing cellular protection against various stress conditions.
An enzyme of the lyase class that catalyzes the cleavage of fructose 1,6-biphosphate to form dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. The enzyme also acts on (3S,4R)-ketose 1-phosphates. The yeast and bacterial enzymes are zinc proteins. (Enzyme Nomenclature, 1992) E.C. 4.1.2.13.
Lengthy and continuous deprivation of food. (Stedman, 25th ed)
Acetyl CoA participates in the biosynthesis of fatty acids and sterols, in the oxidation of fatty acids and in the metabolism of many amino acids. It also acts as a biological acetylating agent.
A group of enzymes that catalyzes the conversion of ATP and D-glucose to ADP and D-glucose 6-phosphate. They are found in invertebrates and microorganisms, and are highly specific for glucose. (Enzyme Nomenclature, 1992) EC 2.7.1.2.
A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
'Ketosis' is a metabolic state characterized by an elevated concentration of ketone bodies in the blood, typically occurring during fasting, carbohydrate restriction, or in uncontrolled diabetes, and can lead to a shift in the body's primary energy source from glucose to fatty acids and ketones.
A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.
Proteins found in any species of bacterium.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A rather large group of enzymes comprising not only those transferring phosphate but also diphosphate, nucleotidyl residues, and others. These have also been subdivided according to the acceptor group. (From Enzyme Nomenclature, 1992) EC 2.7.
Enzymes which catalyze the hydrolysis of carboxylic acid esters with the formation of an alcohol and a carboxylic acid anion.
2-Deoxy-D-arabino-hexose. An antimetabolite of glucose with antiviral activity.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from GLUTAMIC ACID and AMMONIA. It is the principal carrier of NITROGEN in the body and is an important energy source for many cells.
Organic compounds that contain phosphorus as an integral part of the molecule. Included under this heading is broad array of synthetic compounds that are used as PESTICIDES and DRUGS.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.

A possible role for the pentose phosphate pathway of spermatozoa in gamete fusion in the mouse. (1/487)

Glucose metabolism is essential for successful gamete fusion in the mouse. Although the metabolic activity of the oocyte does not appear to play a significant role in the fusion step, the metabolic role of the spermatozoon is not known. The aim of this study was therefore to characterize the role of glucose metabolism in mouse spermatozoa. Initially, the high-affinity glucose transporter GLUT3 was identified in mouse sperm. In characterizing the glucose metabolism of mouse sperm, we have shown 1) that mouse epididymal spermatozoa have a functional pentose phosphate pathway (PPP), implying that they produce NADPH, which is required for reducing reactions, and ribose 5-phosphate, which is required for nucleic acid synthesis; and 2) that sperm are able to fuse with the oocyte when NADPH is substituted for glucose, suggesting that sperm need to produce NADPH via the PPP in order to be able to achieve fertilization. The existence of an NADPH-regulated event that influences the ability of the sperm to fuse with the oocyte is envisaged.  (+info)

Characterization of glycolysis and pentose phosphate pathway activity during sperm entry into the mouse oocyte. (2/487)

Studying the events that occur during gamete fusion and sperm decondensation in the oocyte remains difficult because sperm-oocyte fusion and subsequent sperm decondensation represent a short part of the fertilization process, and their exact timing is difficult to determine. There is therefore a need for greater understanding of the events that occur during this period. The main purpose of this study was to examine the metabolic aspects of this time frame by characterizing glucose metabolism (glycolytic and pentose phosphate pathway [PPP] activities) during sperm fusion and decondensation into zona-free oocytes in mice. The metabolism of glucose through both glycolysis and the PPP was measured in ovulated MII oocytes, free of cumulus cells, and the levels of glucose metabolized were found to be low. Upon sperm entry, both glycolytic and PPP activity increased substantially. To determine whether this elevation in glucose metabolism was part of the activation process, the metabolism of parthenogenetically activated oocytes was measured, and no increase in metabolism was observed. The characterization of glucose metabolism during sperm fusion and decondensation into the oocyte, and comparison to parthenogenetically activated oocytes, showed that the fertilizing sperm is responsible for an increase in both glycolytic and PPP activity during fusion and/or decondensation. The significance of this observation during the fertilization process and for the developing embryo is as yet unclear and warrants further investigation.  (+info)

In vivo operation of the pentose phosphate pathway in frog oocytes is limited by NADP+ availability. (3/487)

Evolution of CO2 from labelled glucose microinjected into frog oocytes in vivo may be ascribed to the pentose-P pathway, as measured by radioactive CO2 production from [1-(14)C] and [6-(14)C]glucose. Coinjection of NADP+ and [14C]glucose significantly stimulated 14CO2 production. The effect depends on the amount of NADP+ injected, half maximal stimulation being obtained at 0.13 mM. The increase in CO2 production was also observed with microinjected glucose-1-P, glucose-6-P or fructose-6-P used as substrates. Phenazine methosulfate, mimicked the effects of NADP+. A high NADPH/NADP+ ratio of 4.3 was found in the cells, the intracellular concentration of NADP+ being 19 microM.  (+info)

METATOOL: for studying metabolic networks. (4/487)

MOTIVATION: To reconstruct metabolic pathways from biochemical and/or genome sequence data, the stoichiometric and thermodynamic feasibility of the pathways has to be tested. This is achieved by characterizing the admissible region of flux distributions in steady state. This region is spanned by what can be called a convex basis. The concept of 'elementary flux modes' provides a mathematical tool to define all metabolic routes that are feasible in a given metabolic network. In addition, we define 'enzyme subsets' to be groups of enzymes that operate together in fixed flux proportions in all steady states of the system. RESULTS: Algorithms for computing the convex basis and elementary modes developed earlier are briefly reviewed. A newly developed algorithm for detecting all enzyme subsets in a given network is presented. All of these algorithms have been implemented in a novel computer program named METATOOL, whose features are outlined here. The algorithms are illustrated by an example taken from sugar metabolism. AVAILABILITY: METATOOL is available from ftp://bmsdarwin.brookes.ac. uk/pub/software/ibmpc/metatool. SUPPLEMENTARY INFORMATION: http://www. biologie.hu-berlin.de/biophysics/Theory/tpfeiffer/metatoo l.html  (+info)

Metabolism of radiolabeled glucose by mouse oocytes and oocyte-cumulus cell complexes. (5/487)

This study was carried out to examine the metabolism of [1-14C]-, [6-14C]-, and [5-3H]glucose by oocyte-cumulus cell complexes (OCC) and denuded oocytes (DO) and to test the hypothesis that metabolism of glucose through the pentose phosphate pathway is associated with meiotic induction. OCC or DO were cultured in hanging drops suspended from the cap of a microfuge tube, with NaOH serving as a trap to collect released 3H2O or 14CO2. Preliminary experiments established that this culture system supports both spontaneous and ligand-induced meiotic maturation. An initial time course experiment (1.5-6 h) showed that hypoxanthine-treated OCC from eCG-primed animals metabolized glucose principally via glycolysis, with an increase to 2.7-fold in response to FSH. Though more [1-14C]glucose was oxidized than [6-14C]glucose, its metabolism was about two orders of magnitude less than that of [5-3H]glucose. Also, FSH significantly increased oxidation of [1-14C]glucose but not [6-14C]glucose, indicating a preferential activation of the pentose phosphate pathway. Pyrroline carboxylate, an activator of the pentose phosphate pathway, increased the activity of this pathway to over 2-fold but failed to affect glucose oxidation through the tricarboxylic acid cycle. Glycolytic metabolism was increased by 25%. The addition of pyruvate to pyruvate-free medium resulted in significant reduction in the metabolism of all three glucose analogues. In OCC retrieved from hCG-injected, primed mice and cultured under hormone-free conditions, metabolic responses were similar to those in FSH-treated complexes cultured in hypoxanthine. DO metabolized glucose, but at a much reduced rate when compared to OCC. Pyruvate reduced the consumption of all three glucose analogues by DO. Pyrroline carboxylate reduced [5-3H]glucose metabolism by DO but had little effect on [1-14C]- and [6-14C]glucose oxidation. These data demonstrate metabolism of glucose by both DO and OCC, but reveal that cumulus cells are more active than the oocyte in this regard. In addition, induction of maturation by FSH, hCG, or pyrroline carboxylate was accompanied by a significant increase in the oxidation of [1-14C]glucose but not [6-14C]glucose by OCC, supporting a proposed role for the pentose phosphate pathway in meiotic induction.  (+info)

Hyperproduction of tryptophan by Corynebacterium glutamicum with the modified pentose phosphate pathway. (6/487)

A classically derived tryptophan-producing Corynebacterium glutamicum strain was recently significantly improved both by plasmid-mediated amplification of the genes for the rate-limiting enzymes in the terminal pathways and by construction of a plasmid stabilization system so that it produced more tryptophan. This engineered strain, KY9218 carrying pKW9901, produced 50 g of tryptophan per liter from sucrose after 80 h in fed-batch cultivation without antibiotic pressure. Analysis of carbon balances showed that at the late stage of the fermentation, tryptophan yield decreased with a concomitant increase in CO2 yield, suggesting a transition in the distribution of carbon flow from aromatic biosynthesis toward the tricarboxylic acid cycle via glycolysis. To circumvent this transition by increasing the supply of erythrose 4-phosphate, a direct precursor of aromatic biosynthesis, the transketolase gene of C. glutamicum was coamplified in the engineered strain by using low- and high-copy-number plasmids which were compatible with the resident plasmid pKW9901. The presence of the gene in low copy numbers contributed to improvement of tryptophan yield, especially at the late stage, and led to accumulation of more tryptophan (57 g/liter) than did its absence, while high-copy-number amplification of the gene resulted in a tryptophan production level even lower than that resulting from the absence of the gene due to reduced growth and sugar consumption. In order to assemble all the cloned genes onto a low-copy-number plasmid, the high-copy-number origin of pKW9901 was replaced with the low-copy-number one, generating low-copy-number plasmid pSW9911, and the transketolase gene was inserted to yield pIK9960. The pSW9911-carrying producer showed almost the same fermentation profiles as the pKW9901 carrier in fed-batch cultivation without antibiotic pressure. Under the same culture conditions, however, the pIK9960 carrier achieved a final tryptophan titer of 58 g/liter, which represented a 15% enhancement over the titers achieved by the pKW9901 and pSW9911 carriers.  (+info)

Vestigial respiratory burst activity in wound macrophages. (7/487)

Macrophages from experimental wounds in rats were tested for their capacity to generate reactive oxygen intermediates. Measurements of superoxide and H2O2 release, O-2-dependent lucigenin chemiluminescence, oxygen consumption, hexose monophosphate shunt flux, and NADPH oxidase activity in cell lysates indicated, at best, the presence of a vestigial respiratory burst response in these cells. The inability of wound cells to release O-2 was not rekindled by priming with endotoxin or interferon-gamma in vivo or in vitro. NADPH oxidase activity in a cell-free system demonstrated that wound macrophage membranes, but not their cytosols, were capable of sustaining maximal rates of O-2 production when mixed with their corresponding counterparts from human neutrophils. Immune detection experiments showed wound macrophages to be particularly deficient in the cytosolic component of the NADPH oxidase p47-phox. Addition of recombinant p47-phox to the human neutrophil-cell membrane/wound macrophage cytosol cell-free oxidase assay, however, failed to support O-2 production. Present findings indicate an unexpected deficit of wound macrophages in their capacity to generate reactive oxygen intermediates.  (+info)

Evidence for the presence of the reductive pentose phosphate cycle in a filamentous anoxygenic photosynthetic bacterium, Oscillochloris trichoides strain DG-6. (8/487)

Studies on autotrophic CO2 fixation by the filamentous anoxygenic photosynthetic bacterium Oscillochloris trichoides strain DG-6 demonstrated that, unlike other green bacteria, this organism metabolized CO2 via the reductive pentose phosphate cycle. Both key enzymes of this cycle--ribulose-1,5-bisphosphate carboxylase/oxygenase and phosphoribulokinase--were detected in cell extracts. The main product of ribulose 1,5-bisphosphate-dependent CO2 fixation was 3-phosphoglyceric acid. KCN, which is known to be a competitive inhibitor of ribulose-1,5-bisphosphate carboxylase/oxygenase, completely inhibited the CO2 assimilation by whole cells as well as by cell extracts of O. trichoides. The 13C/12C carbon isotope fractionation during photoautotrophic growth of O. trichoides was -19.7/1000, which is close to that obtained for autotrophic organisms that use ribulose-1,5-bisphosphate carboxylase as the primary carboxylation enzyme. Cell extracts of O. trichoides contained all the enzymes of the tricarboxylic acid cycle except 2-oxoglutarate dehydrogenase. No activity of isocitrate lyase, a key enzyme of the glyoxylate shunt, was found in cell extracts of O. trichoides DG-6.  (+info)

The Pentose Phosphate Pathway (also known as the Hexose Monophosphate Shunt or HMP Shunt) is a metabolic pathway that runs parallel to glycolysis. It serves two major functions:

1. Providing reducing equivalents in the form of NADPH for reductive biosynthesis and detoxification processes.
2. Generating ribose-5-phosphate, a pentose sugar used in the synthesis of nucleotides and nucleic acids (DNA and RNA).

This pathway begins with the oxidation of glucose-6-phosphate to form 6-phosphogluconolactone, catalyzed by the enzyme glucose-6-phosphate dehydrogenase. The resulting NADPH is used in various anabolic reactions and antioxidant defense systems.

The Pentose Phosphate Pathway also includes a series of reactions called the non-oxidative branch, which interconverts various sugars to meet cellular needs for different types of monosaccharides. These conversions are facilitated by several enzymes including transketolase and transaldolase.

Transaldolase is not a medical term per se, but it is a term used in biochemistry and molecular biology. Transaldolase is an enzyme involved in the pentose phosphate pathway (PPP), which is a metabolic pathway that supplies reducing energy to cells by converting glucose-6-phosphate into ribulose-5-phosphate, a key intermediate in the synthesis of nucleotides.

The medical relevance of transaldolase lies in its role in maintaining cellular redox balance and providing precursors for nucleic acid synthesis. Defects in the PPP can lead to various metabolic disorders, including some forms of congenital cataracts, neurological dysfunction, and growth retardation. However, specific diseases or conditions directly attributed to transaldolase deficiency are not well-established.

Pentose phosphates are monosaccharides that contain five carbon atoms and one phosphate group. They play a crucial role in various metabolic pathways, including the pentose phosphate pathway (PPP), which is a major source of NADPH and ribose-5-phosphate for the synthesis of nucleotides.

The pentose phosphate pathway involves two main phases: the oxidative phase and the non-oxidative phase. In the oxidative phase, glucose-6-phosphate is converted to ribulose-5-phosphate, producing NADPH and CO2 as byproducts. Ribulose-5-phosphate can then be further metabolized in the non-oxidative phase to produce other pentose phosphates or converted back to glucose-6-phosphate through a series of reactions.

Pentose phosphates are also important intermediates in the synthesis of nucleotides, coenzymes, and other metabolites. Abnormalities in pentose phosphate pathway enzymes can lead to various metabolic disorders, such as defects in erythrocyte function and increased susceptibility to oxidative stress.

Transketolase is an enzyme found in most organisms, from bacteria to humans. It plays a crucial role in the pentose phosphate pathway (PPP), which is a metabolic pathway that runs alongside glycolysis in the cell cytoplasm. The PPP provides an alternative way of generating energy and also serves to provide building blocks for new cellular components, particularly nucleotides.

Transketolase functions by catalyzing the transfer of a two-carbon ketol group from a ketose (a sugar containing a ketone functional group) to an aldose (a sugar containing an aldehyde functional group). This reaction forms a new ketose and an aldose, effectively converting three-carbon sugars into five-carbon sugars, or vice versa.

In humans, transketolase is essential for the production of NADPH, an important reducing agent in the cell, and for the synthesis of certain amino acids and nucleotides. Deficiencies in this enzyme can lead to metabolic disorders such as pentosuria.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), also known as Glucosephosphate Dehydrogenase, is an enzyme that plays a crucial role in cellular metabolism, particularly in the glycolytic pathway. It catalyzes the conversion of glyceraldehyde 3-phosphate (G3P) to 1,3-bisphosphoglycerate (1,3-BPG), while also converting nicotinamide adenine dinucleotide (NAD+) to its reduced form NADH. This reaction is essential for the production of energy in the form of adenosine triphosphate (ATP) during cellular respiration. GAPDH has been widely used as a housekeeping gene in molecular biology research due to its consistent expression across various tissues and cells, although recent studies have shown that its expression can vary under certain conditions.

Phosphogluconate dehydrogenase (PGD) is an enzyme that plays a crucial role in the pentose phosphate pathway, which is a metabolic pathway that supplies reducing energy to cells by converting glucose into ribose-5-phosphate and NADPH.

PGD catalyzes the third step of this pathway, in which 6-phosphogluconate is converted into ribulose-5-phosphate, with the concurrent reduction of NADP+ to NADPH. This reaction is essential for the generation of NADPH, which serves as a reducing agent in various cellular processes, including fatty acid synthesis and antioxidant defense.

Deficiencies in PGD can lead to several metabolic disorders, such as congenital nonspherocytic hemolytic anemia, which is characterized by the premature destruction of red blood cells due to a defect in the pentose phosphate pathway.

6-Aminonicotinamide is a pharmacological compound that is an analog of nicotinamide, which is the amide form of vitamin B3 (niacin). Chemically, 6-Aminonicotinamide has a structure similar to nicotinamide, but with an amino group (-NH2) replacing a hydrogen atom at the 6th position of the pyridine ring.

This compound has been used in research to study the biochemical pathways related to nicotinamide and its role in cellular metabolism. It is known to inhibit the activity of certain enzymes, including nicotinamide phosphoribosyltransferase (NAMPT), which plays a crucial role in the biosynthesis of NAD+, an essential coenzyme involved in various redox reactions and energy metabolism in cells.

Due to its inhibitory effects on NAMPT, 6-Aminonicotinamide has been investigated as a potential therapeutic agent for cancer treatment, as disrupting NAD+ biosynthesis may selectively target and kill cancer cells with high metabolic demands. However, the use of 6-Aminonicotinamide in clinical settings is not yet established, and further research is needed to determine its safety and efficacy.

Ribulose phosphates are organic compounds that play a crucial role in the Calvin cycle, which is a part of photosynthesis. The Calvin cycle is the process by which plants, algae, and some bacteria convert carbon dioxide into glucose and other simple sugars.

Ribulose phosphates are sugar phosphates that contain five carbon atoms and have the chemical formula C5H10O5P. They exist in two forms: ribulose 5-phosphate (Ru5P) and ribulose 1,5-bisphosphate (RuBP).

Ribulose 1,5-bisphosphate is the starting point for carbon fixation in the Calvin cycle. In this process, an enzyme called RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) catalyzes the reaction between RuBP and carbon dioxide to form two molecules of 3-phosphoglycerate, which are then converted into glucose and other sugars.

Ribulose phosphates are also involved in other metabolic pathways, such as the pentose phosphate pathway, which generates reducing power in the form of NADPH and produces ribose-5-phosphate, a precursor for nucleotide synthesis.

Ribose monophosphates are organic compounds that play a crucial role in the metabolism of cells, particularly in energy transfer and nucleic acid synthesis. A ribose monophosphate is formed by the attachment of a phosphate group to a ribose molecule, which is a type of sugar known as a pentose.

In biochemistry, there are two important ribose monophosphates:

1. Alpha-D-Ribose 5-Phosphate (ADP-Ribose): This compound serves as an essential substrate in various cellular processes, including DNA repair, chromatin remodeling, and protein modification. The enzyme that catalyzes the formation of ADP-ribose is known as poly(ADP-ribose) polymerase (PARP).
2. Ribulose 5-Phosphate: This compound is a key intermediate in the Calvin cycle, which is the process by which plants and some bacteria convert carbon dioxide into glucose during photosynthesis. Ribulose 5-phosphate is formed from ribose 5-phosphate through a series of enzymatic reactions.

Ribose monophosphates are essential for the proper functioning of cells and have implications in various physiological processes, as well as in certain disease states.

Glycolysis is a fundamental metabolic pathway that occurs in the cytoplasm of cells, consisting of a series of biochemical reactions. It's the process by which a six-carbon glucose molecule is broken down into two three-carbon pyruvate molecules. This process generates a net gain of two ATP molecules (the main energy currency in cells), two NADH molecules, and two water molecules.

Glycolysis can be divided into two stages: the preparatory phase (or 'energy investment' phase) and the payoff phase (or 'energy generation' phase). During the preparatory phase, glucose is phosphorylated twice to form glucose-6-phosphate and then converted to fructose-1,6-bisphosphate. These reactions consume two ATP molecules but set up the subsequent breakdown of fructose-1,6-bisphosphate into triose phosphates in the payoff phase. In this second stage, each triose phosphate is further oxidized and degraded to produce one pyruvate molecule, one NADH molecule, and one ATP molecule through substrate-level phosphorylation.

Glycolysis does not require oxygen to proceed; thus, it can occur under both aerobic (with oxygen) and anaerobic (without oxygen) conditions. In the absence of oxygen, the pyruvate produced during glycolysis is further metabolized through fermentation pathways such as lactic acid fermentation or alcohol fermentation to regenerate NAD+, which is necessary for glycolysis to continue.

In summary, glycolysis is a crucial process in cellular energy metabolism, allowing cells to convert glucose into ATP and other essential molecules while also serving as a starting point for various other biochemical pathways.

Glucose-6-phosphate (G6P) is a vital intermediate compound in the metabolism of glucose, which is a simple sugar that serves as a primary source of energy for living organisms. G6P plays a critical role in both glycolysis and gluconeogenesis pathways, contributing to the regulation of blood glucose levels and energy production within cells.

In biochemistry, glucose-6-phosphate is defined as:

A hexose sugar phosphate ester formed by the phosphorylation of glucose at the 6th carbon atom by ATP in a reaction catalyzed by the enzyme hexokinase or glucokinase. This reaction is the first step in both glycolysis and glucose storage (glycogen synthesis) processes, ensuring that glucose can be effectively utilized for energy production or stored for later use.

G6P serves as a crucial metabolic branch point, leading to various pathways such as:

1. Glycolysis: In the presence of sufficient ATP and NAD+ levels, G6P is further metabolized through glycolysis to generate pyruvate, which enters the citric acid cycle for additional energy production in the form of ATP, NADH, and FADH2.
2. Gluconeogenesis: During periods of low blood glucose levels, G6P can be synthesized back into glucose through the gluconeogenesis pathway, primarily occurring in the liver and kidneys. This process helps maintain stable blood glucose concentrations and provides energy to cells when dietary intake is insufficient.
3. Pentose phosphate pathway (PPP): A portion of G6P can be shunted into the PPP, an alternative metabolic route that generates NADPH, ribose-5-phosphate for nucleotide synthesis, and erythrose-4-phosphate for aromatic amino acid production. The PPP is essential in maintaining redox balance within cells and supporting biosynthetic processes.

Overall, glucose-6-phosphate plays a critical role as a central metabolic intermediate, connecting various pathways to regulate energy homeostasis, redox balance, and biosynthesis in response to cellular demands and environmental cues.

Glucose is a simple monosaccharide (or single sugar) that serves as the primary source of energy for living organisms. It's a fundamental molecule in biology, often referred to as "dextrose" or "grape sugar." Glucose has the molecular formula C6H12O6 and is vital to the functioning of cells, especially those in the brain and nervous system.

In the body, glucose is derived from the digestion of carbohydrates in food, and it's transported around the body via the bloodstream to cells where it can be used for energy. Cells convert glucose into a usable form through a process called cellular respiration, which involves a series of metabolic reactions that generate adenosine triphosphate (ATP)—the main currency of energy in cells.

Glucose is also stored in the liver and muscles as glycogen, a polysaccharide (multiple sugar) that can be broken down back into glucose when needed for energy between meals or during physical activity. Maintaining appropriate blood glucose levels is crucial for overall health, and imbalances can lead to conditions such as diabetes mellitus.

Phosphates, in a medical context, refer to the salts or esters of phosphoric acid. Phosphates play crucial roles in various biological processes within the human body. They are essential components of bones and teeth, where they combine with calcium to form hydroxyapatite crystals. Phosphates also participate in energy transfer reactions as phosphate groups attached to adenosine diphosphate (ADP) and adenosine triphosphate (ATP). Additionally, they contribute to buffer systems that help maintain normal pH levels in the body.

Abnormal levels of phosphates in the blood can indicate certain medical conditions. High phosphate levels (hyperphosphatemia) may be associated with kidney dysfunction, hyperparathyroidism, or excessive intake of phosphate-containing products. Low phosphate levels (hypophosphatemia) might result from malnutrition, vitamin D deficiency, or certain diseases affecting the small intestine or kidneys. Both hypophosphatemia and hyperphosphatemia can have significant impacts on various organ systems and may require medical intervention.

NADP (Nicotinamide Adenine Dinucleotide Phosphate) is a coenzyme that plays a crucial role as an electron carrier in various redox reactions in the human body. It exists in two forms: NADP+, which functions as an oxidizing agent and accepts electrons, and NADPH, which serves as a reducing agent and donates electrons.

NADPH is particularly important in anabolic processes, such as lipid and nucleotide synthesis, where it provides the necessary reducing equivalents to drive these reactions forward. It also plays a critical role in maintaining the cellular redox balance by participating in antioxidant defense mechanisms that neutralize harmful reactive oxygen species (ROS).

In addition, NADP is involved in various metabolic pathways, including the pentose phosphate pathway and the Calvin cycle in photosynthesis. Overall, NADP and its reduced form, NADPH, are essential molecules for maintaining proper cellular function and energy homeostasis.

The Citric Acid Cycle, also known as the Krebs cycle or tricarboxylic acid (TCA) cycle, is a crucial metabolic pathway in the cell's powerhouse, the mitochondria. It plays a central role in the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins, into carbon dioxide and high-energy electrons. This process generates energy in the form of ATP (adenosine triphosphate), reducing equivalents (NADH and FADH2), and water.

The cycle begins with the condensation of acetyl-CoA with oxaloacetate, forming citrate. Through a series of enzyme-catalyzed reactions, citrate is converted back to oxaloacetate, releasing two molecules of carbon dioxide, one GTP (guanosine triphosphate), three NADH, one FADH2, and regenerating oxaloacetate to continue the cycle. The reduced coenzymes (NADH and FADH2) then donate their electrons to the electron transport chain, driving ATP synthesis through chemiosmosis. Overall, the Citric Acid Cycle is a vital part of cellular respiration, connecting various catabolic pathways and generating energy for the cell's metabolic needs.

Ribose is a simple carbohydrate, specifically a monosaccharide, which means it is a single sugar unit. It is a type of sugar known as a pentose, containing five carbon atoms. Ribose is a vital component of ribonucleic acid (RNA), one of the essential molecules in all living cells, involved in the process of transcribing and translating genetic information from DNA to proteins. The term "ribose" can also refer to any sugar alcohol derived from it, such as D-ribose or Ribitol.

Sugar phosphates are organic compounds that play crucial roles in various biological processes, particularly in the field of genetics and molecular biology. They are formed by the attachment of a phosphate group to a sugar molecule, most commonly to the 5-carbon sugar ribose or deoxyribose.

In genetics, sugar phosphates form the backbone of nucleic acids, such as DNA and RNA. In DNA, the sugar phosphate backbone consists of alternating deoxyribose (a sugar) and phosphate groups, linked together by covalent bonds between the 5' carbon atom of one sugar molecule and the 3' carbon atom of another sugar molecule. This forms a long, twisted ladder-like structure known as a double helix.

Similarly, in RNA, the sugar phosphate backbone is formed by ribose (a sugar) and phosphate groups, creating a single-stranded structure that can fold back on itself to form complex shapes. These sugar phosphate backbones provide structural support for the nucleic acids and help to protect the genetic information stored within them.

Sugar phosphates also play important roles in energy metabolism, as they are involved in the formation and breakdown of high-energy compounds such as ATP (adenosine triphosphate) and GTP (guanosine triphosphate). These molecules serve as energy currency for cells, storing and releasing energy as needed to power various cellular processes.

Xylose is a type of sugar that is commonly found in plants and wood. In the context of medical definitions, xylose is often used in tests to assess the function of the small intestine. The most common test is called the "xylose absorption test," which measures the ability of the small intestine to absorb this sugar.

In this test, a patient is given a small amount of xylose to drink, and then several blood and/or urine samples are collected over the next few hours. The amount of xylose that appears in these samples is measured and used to determine how well the small intestine is absorbing nutrients.

Abnormal results on a xylose absorption test can indicate various gastrointestinal disorders, such as malabsorption syndromes, celiac disease, or bacterial overgrowth in the small intestine.

Gluconates are a group of salts and esters derived from gluconic acid, a weak organic acid that is naturally produced in the human body during the metabolism of carbohydrates. In medical contexts, gluconates are often used as a source of the essential mineral ions, such as calcium, magnesium, and iron, which are necessary for various bodily functions.

Gluconate salts are commonly used in pharmaceutical and nutritional supplements because they are highly soluble in water, making them easy to absorb and utilize by the body. For example, calcium gluconate is a common treatment for hypocalcemia (low blood calcium levels), while magnesium gluconate is used to treat magnesium deficiency.

Gluconates may also be used as preservatives in some medical products, such as intravenous solutions and eye drops, due to their ability to inhibit the growth of bacteria and other microorganisms. Overall, gluconates are a versatile class of compounds with important applications in medicine and health.

Xylulose is a ketopentose, which is a type of sugar (monosaccharide) with five carbon atoms and a ketone functional group. It is a less common sugar compared to glucose or fructose. Xylulose can be found in small amounts in some fruits and vegetables, and it can also be produced in the human body during the metabolism of certain substances like xylitol, a sugar alcohol used as a sweetener. In the body, xylulose is converted into xylulose-5-phosphate, which plays a role in the pentose phosphate pathway, a metabolic route that generates reducing power (NADPH) for biosynthesis and provides precursors for nucleotide synthesis.

Aldose-ketose isomerases are a group of enzymes that catalyze the interconversion between aldoses and ketoses, which are different forms of sugars. These enzymes play an essential role in carbohydrate metabolism by facilitating the reversible conversion of aldoses to ketoses and vice versa.

Aldoses are sugars that contain a carbonyl group (a functional group consisting of a carbon atom double-bonded to an oxygen atom) at the end of the carbon chain, while ketoses have their carbonyl group located in the middle of the chain. The isomerization process catalyzed by aldose-ketose isomerases helps maintain the balance between these two forms of sugars and enables cells to utilize them more efficiently for energy production and other metabolic processes.

There are several types of aldose-ketose isomerases, including:

1. Triose phosphate isomerase (TPI): This enzyme catalyzes the interconversion between dihydroxyacetone phosphate (a ketose) and D-glyceraldehyde 3-phosphate (an aldose), which are both trioses (three-carbon sugars). TPI plays a crucial role in glycolysis, the metabolic pathway that breaks down glucose to produce energy.
2. Xylulose kinase: This enzyme is involved in the pentose phosphate pathway, which is a metabolic route that generates reducing equivalents (NADPH) and pentoses for nucleic acid synthesis. Xylulose kinase catalyzes the conversion of D-xylulose (a ketose) to D-xylulose 5-phosphate, an important intermediate in the pentose phosphate pathway.
3. Ribulose-5-phosphate 3-epimerase: This enzyme is also part of the pentose phosphate pathway and catalyzes the interconversion between D-ribulose 5-phosphate (an aldose) and D-xylulose 5-phosphate (a ketose).
4. Phosphoglucomutase: This enzyme catalyzes the reversible conversion of glucose 1-phosphate (an aldose) to glucose 6-phosphate (an aldose), which is an important intermediate in both glycolysis and gluconeogenesis.
5. Phosphomannomutase: This enzyme catalyzes the reversible conversion of mannose 1-phosphate (a ketose) to mannose 6-phosphate (an aldose), which is involved in the biosynthesis of complex carbohydrates.

These are just a few examples of enzymes that catalyze the interconversion between aldoses and ketoses, highlighting their importance in various metabolic pathways.

Erythritol is a type of sugar alcohol (a carbohydrate that is metabolized differently than other sugars) used as a sugar substitute in food and drinks. It has about 0.24 calories per gram and contains almost no carbohydrates or sugar, making it a popular choice for people with diabetes or those following low-carb diets. Erythritol is naturally found in some fruits and fermented foods, but most commercial erythritol is made from cornstarch. It has a sweet taste similar to sugar but contains fewer calories and does not raise blood sugar levels.

Glucose-6-phosphate isomerase (GPI) is an enzyme involved in the glycolytic and gluconeogenesis pathways. It catalyzes the interconversion of glucose-6-phosphate (G6P) and fructose-6-phosphate (F6P), which are key metabolic intermediates in these pathways. This reaction is a reversible step that helps maintain the balance between the breakdown and synthesis of glucose in the cell.

In glycolysis, GPI converts G6P to F6P, which subsequently gets converted to fructose-1,6-bisphosphate (F1,6BP) by the enzyme phosphofructokinase-1 (PFK-1). In gluconeogenesis, the reaction is reversed, and F6P is converted back to G6P.

Deficiency or dysfunction of Glucose-6-phosphate isomerase can lead to various metabolic disorders, such as glycogen storage diseases and hereditary motor neuropathies.

A pentose is a monosaccharide (simple sugar) that contains five carbon atoms. The name "pentose" comes from the Greek word "pente," meaning five, and "ose," meaning sugar. Pentoses play important roles in various biological processes, such as serving as building blocks for nucleic acids (DNA and RNA) and other biomolecules.

Some common pentoses include:

1. D-Ribose - A naturally occurring pentose found in ribonucleic acid (RNA), certain coenzymes, and energy-carrying molecules like adenosine triphosphate (ATP).
2. D-Deoxyribose - A pentose that lacks a hydroxyl (-OH) group on the 2' carbon atom, making it a key component of deoxyribonucleic acid (DNA).
3. Xylose - A naturally occurring pentose found in various plants and woody materials; it is used as a sweetener and food additive.
4. Arabinose - Another plant-derived pentose, arabinose can be found in various fruits, vegetables, and grains. It has potential applications in the production of biofuels and other bioproducts.
5. Lyxose - A less common pentose that can be found in some polysaccharides and glycoproteins.

Pentoses are typically less sweet than hexoses (six-carbon sugars) like glucose or fructose, but they still contribute to the overall sweetness of many foods and beverages.

Glyceraldehyde 3-phosphate (G3P) is a crucial intermediate in both glycolysis and gluconeogenesis metabolic pathways. It is an triose sugar phosphate, which means it contains three carbon atoms and has a phosphate group attached to it.

In the glycolysis process, G3P is produced during the third step of the process from the molecule dihydroxyacetone phosphate (DHAP) via the enzyme triosephosphate isomerase. In the following steps, G3P is converted into 1,3-bisphosphoglycerate, which eventually leads to the production of ATP and NADH.

In gluconeogenesis, G3P is produced from the reverse reaction of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase, using the molecule dihydroxyacetone phosphate (DHAP) as a starting point. G3P is then converted into glucose-6-phosphate, which can be further metabolized or released from the cell.

It's important to note that Glyceraldehyde 3-Phosphate plays a key role in energy production and carbohydrate metabolism.

Carbon isotopes are variants of the chemical element carbon that have different numbers of neutrons in their atomic nuclei. The most common and stable isotope of carbon is carbon-12 (^{12}C), which contains six protons and six neutrons. However, carbon can also come in other forms, known as isotopes, which contain different numbers of neutrons.

Carbon-13 (^{13}C) is a stable isotope of carbon that contains seven neutrons in its nucleus. It makes up about 1.1% of all carbon found on Earth and is used in various scientific applications, such as in tracing the metabolic pathways of organisms or in studying the age of fossilized materials.

Carbon-14 (^{14}C), also known as radiocarbon, is a radioactive isotope of carbon that contains eight neutrons in its nucleus. It is produced naturally in the atmosphere through the interaction of cosmic rays with nitrogen gas. Carbon-14 has a half-life of about 5,730 years, which makes it useful for dating organic materials, such as archaeological artifacts or fossils, up to around 60,000 years old.

Carbon isotopes are important in many scientific fields, including geology, biology, and medicine, and are used in a variety of applications, from studying the Earth's climate history to diagnosing medical conditions.

Xylitol is a type of sugar alcohol used as a sugar substitute in various food and dental products. It has a sweet taste similar to sugar but with fewer calories and less impact on blood sugar levels, making it a popular choice for people with diabetes or those looking to reduce their sugar intake. Xylitol is also known to have dental benefits, as it can help prevent tooth decay by reducing the amount of bacteria in the mouth that cause cavities.

Medically speaking, xylitol is classified as a carbohydrate and has a chemical formula of C5H12O5. It occurs naturally in some fruits and vegetables, but most commercial xylitol is produced from corn cobs or other plant materials through a process called hydrogenation. While generally considered safe for human consumption, it can have a laxative effect in large amounts and may be harmful to dogs, so it's important to keep it out of reach of pets.

'Gluconobacter oxydans' is a species of gram-negative, facultatively anaerobic bacteria that are commonly found in various environments such as fruit, flowers, and soil. They are known for their ability to oxidize a variety of alcohols and sugars, including glucose, into their corresponding acids. This makes them important in industrial applications, such as the production of vinegar and other food ingredients. In a medical context, they can sometimes be associated with opportunistic infections, particularly in individuals with weakened immune systems. However, they are not typically considered harmful to healthy individuals.

In the context of medical definitions, 'carbon' is not typically used as a standalone term. Carbon is an element with the symbol C and atomic number 6, which is naturally abundant in the human body and the environment. It is a crucial component of all living organisms, forming the basis of organic compounds, such as proteins, carbohydrates, lipids, and nucleic acids (DNA and RNA).

Carbon forms strong covalent bonds with various elements, allowing for the creation of complex molecules that are essential to life. In this sense, carbon is a fundamental building block of life on Earth. However, it does not have a specific medical definition as an isolated term.

Carbon dioxide (CO2) is a colorless, odorless gas that is naturally present in the Earth's atmosphere. It is a normal byproduct of cellular respiration in humans, animals, and plants, and is also produced through the combustion of fossil fuels such as coal, oil, and natural gas.

In medical terms, carbon dioxide is often used as a respiratory stimulant and to maintain the pH balance of blood. It is also used during certain medical procedures, such as laparoscopic surgery, to insufflate (inflate) the abdominal cavity and create a working space for the surgeon.

Elevated levels of carbon dioxide in the body can lead to respiratory acidosis, a condition characterized by an increased concentration of carbon dioxide in the blood and a decrease in pH. This can occur in conditions such as chronic obstructive pulmonary disease (COPD), asthma, or other lung diseases that impair breathing and gas exchange. Symptoms of respiratory acidosis may include shortness of breath, confusion, headache, and in severe cases, coma or death.

Glucose phosphates are organic compounds that result from the reaction of glucose (a simple sugar) with phosphate groups. These compounds play a crucial role in various metabolic processes, particularly in energy metabolism within cells. The addition of phosphate groups to glucose makes it more reactive and enables it to undergo further reactions that lead to the formation of important molecules such as adenosine triphosphate (ATP), which is a primary source of energy for cellular functions.

One notable example of a glucose phosphate is glucose 1-phosphate, which is an intermediate in several metabolic pathways, including glycogenesis (the process of forming glycogen, a storage form of glucose) and glycolysis (the breakdown of glucose to release energy). Another example is glucose 6-phosphate, which is a key regulator of carbohydrate metabolism and serves as an important intermediate in the pentose phosphate pathway, a metabolic route that generates reducing equivalents (NADPH) and ribose sugars for nucleotide synthesis.

In summary, glucose phosphates are essential compounds in cellular metabolism, facilitating energy production, storage, and utilization.

Aldehyde-lyases are a class of enzymes that catalyze the breakdown or synthesis of molecules involving an aldehyde group through a reaction known as lyase cleavage. This type of reaction results in the removal of a molecule, typically water or carbon dioxide, from the substrate.

In the case of aldehyde-lyases, these enzymes specifically catalyze reactions that involve the conversion of an aldehyde into a carboxylic acid or vice versa. These enzymes are important in various metabolic pathways and play a crucial role in the biosynthesis and degradation of several biomolecules, including carbohydrates, amino acids, and lipids.

The systematic name for this class of enzymes is "ald(e)hyde-lyases." They are classified under EC number 4.3.1 in the Enzyme Commission (EC) system.

Hexose phosphates are organic compounds that consist of a hexose sugar molecule (a monosaccharide containing six carbon atoms, such as glucose or fructose) that has been phosphorylated, meaning that a phosphate group has been added to it. This process is typically facilitated by enzymes called kinases, which transfer a phosphate group from a donor molecule (usually ATP) to the sugar molecule.

Hexose phosphates play important roles in various metabolic pathways, including glycolysis, gluconeogenesis, and the pentose phosphate pathway. For example, glucose-6-phosphate is a key intermediate in both glycolysis and gluconeogenesis, while fructose-6-phosphate and fructose-1,6-bisphosphate are important intermediates in glycolysis. The pentose phosphate pathway, which is involved in the production of NADPH and ribose-5-phosphate, begins with the conversion of glucose-6-phosphate to 6-phosphogluconolactone by the enzyme glucose-6-phosphate dehydrogenase.

Overall, hexose phosphates are important metabolic intermediates that help regulate energy production and utilization in cells.

Carbohydrate metabolism is the process by which the body breaks down carbohydrates into glucose, which is then used for energy or stored in the liver and muscles as glycogen. This process involves several enzymes and chemical reactions that convert carbohydrates from food into glucose, fructose, or galactose, which are then absorbed into the bloodstream and transported to cells throughout the body.

The hormones insulin and glucagon regulate carbohydrate metabolism by controlling the uptake and storage of glucose in cells. Insulin is released from the pancreas when blood sugar levels are high, such as after a meal, and promotes the uptake and storage of glucose in cells. Glucagon, on the other hand, is released when blood sugar levels are low and signals the liver to convert stored glycogen back into glucose and release it into the bloodstream.

Disorders of carbohydrate metabolism can result from genetic defects or acquired conditions that affect the enzymes or hormones involved in this process. Examples include diabetes, hypoglycemia, and galactosemia. Proper management of these disorders typically involves dietary modifications, medication, and regular monitoring of blood sugar levels.

Carbohydrate epimerases are a group of enzymes that catalyze the interconversion of specific stereoisomers (epimers) of carbohydrates by the reversible oxidation and reduction of carbon atoms, usually at the fourth or fifth position. These enzymes play important roles in the biosynthesis and modification of various carbohydrate-containing molecules, such as glycoproteins, proteoglycans, and glycolipids, which are involved in numerous biological processes including cell recognition, signaling, and adhesion.

The reaction catalyzed by carbohydrate epimerases involves the transfer of a hydrogen atom and a proton between two adjacent carbon atoms, leading to the formation of new stereochemical configurations at these positions. This process can result in the conversion of one epimer into another, thereby expanding the structural diversity of carbohydrates and their derivatives.

Carbohydrate epimerases are classified based on the type of substrate they act upon and the specific stereochemical changes they induce. Some examples include UDP-glucose 4-epimerase, which interconverts UDP-glucose and UDP-galactose; UDP-N-acetylglucosamine 2-epimerase, which converts UDP-N-acetylglucosamine to UDP-N-acetylmannosamine; and GDP-fucose synthase, which catalyzes the conversion of GDP-mannose to GDP-fucose.

Understanding the function and regulation of carbohydrate epimerases is crucial for elucidating their roles in various biological processes and developing strategies for targeting them in therapeutic interventions.

Thiamine, also known as vitamin B1, is a water-soluble vitamin that plays a crucial role in certain metabolic reactions, particularly in the conversion of carbohydrates into energy in the body. It is essential for the proper functioning of the heart, nerves, and digestive system. Thiamine acts as a cofactor for enzymes involved in the synthesis of neurotransmitters and the metabolism of carbohydrates, lipids, and proteins. Deficiency in thiamine can lead to serious health complications, such as beriberi (a disease characterized by peripheral neuropathy, muscle wasting, and heart failure) and Wernicke-Korsakoff syndrome (a neurological disorder often seen in alcoholics due to chronic thiamine deficiency). Thiamine is found in various foods, including whole grains, legumes, pork, beef, and fortified foods.

Phosphoribosyl Pyrophosphate (PRPP) is defined as a key intracellular nucleotide metabolite that plays an essential role in the biosynthesis of purine and pyrimidine nucleotides, which are the building blocks of DNA and RNA. PRPP is synthesized from ribose 5-phosphate and ATP by the enzyme PRPP synthase. It contributes a phosphoribosyl group in the conversion of purines and pyrimidines to their corresponding nucleotides, which are critical for various cellular processes such as DNA replication, repair, and gene expression. Abnormal levels of PRPP have been implicated in several genetic disorders, including Lesch-Nyhan syndrome and PRPP synthetase superactivity.

Phosphofructokinase (PFK) is an enzyme that plays a crucial role in regulating glycolysis, which is the metabolic pathway responsible for the conversion of glucose into energy. PFK catalyzes the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate, using a molecule of adenosine triphosphate (ATP) as a source of energy. This reaction is a key regulatory step in glycolysis and is subject to allosteric regulation by various metabolites, such as ATP, ADP, and citrate, that signal the cell's energy status.

There are several isoforms of PFK found in different tissues, including PFK-1 (or muscle PFK) and PFK-2 (or liver PFK), which exhibit tissue-specific patterns of expression and regulation. Mutations in the genes encoding PFK can result in various inherited metabolic disorders, such as Tarui's disease, characterized by exercise intolerance, muscle cramps, and myoglobinuria.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

Arabinose is a simple sugar or monosaccharide that is a stereoisomer of xylose. It is a pentose, meaning it contains five carbon atoms, and is classified as a hexahydroxyhexital because it has six hydroxyl (-OH) groups attached to the carbon atoms. Arabinose is found in various plant polysaccharides, such as hemicelluloses, gums, and pectic substances. It can also be found in some bacteria and yeasts, where it plays a role in their metabolism. In humans, arabinose is not an essential nutrient and must be metabolized by specific enzymes if consumed.

Trioses are simple sugars that contain three carbon atoms and a functional group called a ketone or aldehyde. They are the simplest type of sugar molecule, after monosaccharides such as glyceraldehyde and dihydroxyacetone.

Triose sugars can exist in two structural forms:

* Dihydroxyacetone (DHA), which is a ketotriose with the formula CH2OH-CO-CH2OH, and
* Glyceraldehyde (GA), which is an aldotriose with the formula HO-CHOH-CHO.

Trioses play important roles in various metabolic pathways, including glycolysis, gluconeogenesis, and the Calvin cycle of photosynthesis. In particular, DHA and GA are intermediates in the conversion of glucose to pyruvate during glycolysis, and they are also produced from pyruvate during gluconeogenesis.

Trioses can be synthesized chemically or biochemically through various methods, such as enzymatic reactions or microbial fermentation. They have potential applications in the food, pharmaceutical, and chemical industries, as they can serve as building blocks for more complex carbohydrates or as precursors for other organic compounds.

Metabolic networks and pathways refer to the complex interconnected series of biochemical reactions that occur within cells to maintain life. These reactions are catalyzed by enzymes and are responsible for the conversion of nutrients into energy, as well as the synthesis and breakdown of various molecules required for cellular function.

A metabolic pathway is a series of chemical reactions that occur in a specific order, with each reaction being catalyzed by a different enzyme. These pathways are often interconnected, forming a larger network of interactions known as a metabolic network.

Metabolic networks can be represented as complex diagrams or models, which show the relationships between different pathways and the flow of matter and energy through the system. These networks can help researchers to understand how cells regulate their metabolism in response to changes in their environment, and how disruptions to these networks can lead to disease.

Some common examples of metabolic pathways include glycolysis, the citric acid cycle (also known as the Krebs cycle), and the pentose phosphate pathway. Each of these pathways plays a critical role in maintaining cellular homeostasis and providing energy for cellular functions.

Sugar alcohols, also known as polyols, are carbohydrates that are chemically similar to sugar but have a different molecular structure. They occur naturally in some fruits and vegetables, but most sugar alcohols used in food products are manufactured.

The chemical structure of sugar alcohols contains a hydroxyl group (-OH) instead of a hydrogen and a ketone or aldehyde group, which makes them less sweet than sugar and have fewer calories. They are not completely absorbed by the body, so they do not cause a rapid increase in blood glucose levels, making them a popular sweetener for people with diabetes.

Common sugar alcohols used in food products include xylitol, sorbitol, mannitol, erythritol, and maltitol. They are often used as sweeteners in sugar-free and low-sugar foods such as candy, chewing gum, baked goods, and beverages.

However, consuming large amounts of sugar alcohols can cause digestive symptoms such as bloating, gas, and diarrhea, due to their partial absorption in the gut. Therefore, it is recommended to consume them in moderation.

Hexokinase is an enzyme that plays a crucial role in the initial step of glucose metabolism, which is the phosphorylation of glucose to form glucose-6-phosphate. This reaction is the first step in most glucose catabolic pathways, including glycolysis, pentose phosphate pathway, and glycogen synthesis.

Hexokinase has a high affinity for glucose, meaning it can bind and phosphorylate glucose even at low concentrations. This property makes hexokinase an important regulator of glucose metabolism in cells. There are four isoforms of hexokinase (I-IV) found in different tissues, with hexokinase IV (also known as glucokinase) being primarily expressed in the liver and pancreas.

In summary, hexokinase is a vital enzyme involved in glucose metabolism, catalyzing the conversion of glucose to glucose-6-phosphate, and playing a crucial role in regulating cellular energy homeostasis.

Transferases are a class of enzymes that facilitate the transfer of specific functional groups (like methyl, acetyl, or phosphate groups) from one molecule (the donor) to another (the acceptor). This transfer of a chemical group can alter the physical or chemical properties of the acceptor molecule and is a crucial process in various metabolic pathways. Transferases play essential roles in numerous biological processes, such as biosynthesis, detoxification, and catabolism.

The classification of transferases is based on the type of functional group they transfer:

1. Methyltransferases - transfer a methyl group (-CH3)
2. Acetyltransferases - transfer an acetyl group (-COCH3)
3. Aminotransferases or Transaminases - transfer an amino group (-NH2 or -NHR, where R is a hydrogen atom or a carbon-containing group)
4. Glycosyltransferases - transfer a sugar moiety (a glycosyl group)
5. Phosphotransferases - transfer a phosphate group (-PO3H2)
6. Sulfotransferases - transfer a sulfo group (-SO3H)
7. Acyltransferases - transfer an acyl group (a fatty acid or similar molecule)

These enzymes are identified and named according to the systematic nomenclature of enzymes developed by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology (IUBMB). The naming convention includes the class of enzyme, the specific group being transferred, and the molecules involved in the transfer reaction. For example, the enzyme that transfers a phosphate group from ATP to glucose is named "glucokinase."

Fermentation is a metabolic process in which an organism converts carbohydrates into alcohol or organic acids using enzymes. In the absence of oxygen, certain bacteria, yeasts, and fungi convert sugars into carbon dioxide, hydrogen, and various end products, such as alcohol, lactic acid, or acetic acid. This process is commonly used in food production, such as in making bread, wine, and beer, as well as in industrial applications for the production of biofuels and chemicals.

Isomerases are a class of enzymes that catalyze the interconversion of isomers of a single molecule. They do this by rearranging atoms within a molecule to form a new structural arrangement or isomer. Isomerases can act on various types of chemical bonds, including carbon-carbon and carbon-oxygen bonds.

There are several subclasses of isomerases, including:

1. Racemases and epimerases: These enzymes interconvert stereoisomers, which are molecules that have the same molecular formula but different spatial arrangements of their atoms in three-dimensional space.
2. Cis-trans isomerases: These enzymes interconvert cis and trans isomers, which differ in the arrangement of groups on opposite sides of a double bond.
3. Intramolecular oxidoreductases: These enzymes catalyze the transfer of electrons within a single molecule, resulting in the formation of different isomers.
4. Mutases: These enzymes catalyze the transfer of functional groups within a molecule, resulting in the formation of different isomers.
5. Tautomeres: These enzymes catalyze the interconversion of tautomers, which are isomeric forms of a molecule that differ in the location of a movable hydrogen atom and a double bond.

Isomerases play important roles in various biological processes, including metabolism, signaling, and regulation.

The metabolome is the complete set of small molecule metabolites, such as carbohydrates, lipids, nucleic acids, and amino acids, present in a biological sample at a given moment. It reflects the physiological state of a cell, tissue, or organism and provides information about the biochemical processes that are taking place. The metabolome is dynamic and constantly changing due to various factors such as genetics, environment, diet, and disease. Studying the metabolome can help researchers understand the underlying mechanisms of health and disease and develop diagnostic tools and treatments for various medical conditions.

Ribose-Phosphate Pyrophosphokinase (PRPS): It is an enzyme involved in the metabolic pathway of nucleotide synthesis. The systematic name for this enzyme is ribose-5-phosphate:ATP phosphotransferase. This enzyme catalyzes the conversion of ribose-5-phosphate and ATP to ribose-1,5-bisphosphate and AMP, plus inorganic pyrophosphate (PPi).

The reaction is:

ribose-5-phosphate + ATP -> ribose-1,5-bisphosphate + AMP + PPi

This enzyme plays a crucial role in the synthesis of purine nucleotides, which are essential for DNA and RNA synthesis. Deficiency or mutations in this enzyme can lead to serious medical conditions such as hereditary sensory neuropathy (HSN) and Arts syndrome.

Plastids are membrane-bound organelles found in the cells of plants and algae. They are responsible for various cellular functions, including photosynthesis, storage of starch, lipids, and proteins, and the production of pigments that give plants their color. The most common types of plastids are chloroplasts (which contain chlorophyll and are involved in photosynthesis), chromoplasts (which contain pigments such as carotenoids and are responsible for the yellow, orange, and red colors of fruits and flowers), and leucoplasts (which do not contain pigments and serve mainly as storage organelles). Plastids have their own DNA and can replicate themselves within the cell.

Heptoses are rare sugars that contain seven carbons in their structure. They are not as common as monosaccharides with 5 or 6 carbons, such as ribose or glucose. An example of a heptose is sedoheptulose, which can be found in some plants and honey. Heptoses can play a role in various biological processes, including cell signaling and metabolism, but they are not as widely studied or well-understood as other types of sugars.

Pyruvic acid, also known as 2-oxopropanoic acid, is a key metabolic intermediate in both anaerobic and aerobic respiration. It is a carboxylic acid with a ketone functional group, making it a β-ketoacid. In the cytosol, pyruvate is produced from glucose during glycolysis, where it serves as a crucial link between the anaerobic breakdown of glucose and the aerobic process of cellular respiration in the mitochondria.

During low oxygen availability or high energy demands, pyruvate can be converted into lactate through anaerobic glycolysis, allowing for the continued production of ATP (adenosine triphosphate) without oxygen. In the presence of adequate oxygen and functional mitochondria, pyruvate is transported into the mitochondrial matrix where it undergoes oxidative decarboxylation to form acetyl-CoA by the enzyme pyruvate dehydrogenase complex (PDC). This reaction also involves the reduction of NAD+ to NADH and the release of CO2. Acetyl-CoA then enters the citric acid cycle, where it is further oxidized to produce energy in the form of ATP, NADH, FADH2, and GTP (guanosine triphosphate) through a series of enzymatic reactions.

In summary, pyruvic acid is a vital metabolic intermediate that plays a significant role in energy production pathways, connecting glycolysis to both anaerobic and aerobic respiration.

Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is a genetic disorder that affects the normal functioning of an enzyme called G6PD. This enzyme is found in red blood cells and plays a crucial role in protecting them from damage.

In people with G6PD deficiency, the enzyme's activity is reduced or absent, making their red blood cells more susceptible to damage and destruction, particularly when they are exposed to certain triggers such as certain medications, infections, or foods. This can lead to a condition called hemolysis, where the red blood cells break down prematurely, leading to anemia, jaundice, and in severe cases, kidney failure.

G6PD deficiency is typically inherited from one's parents in an X-linked recessive pattern, meaning that males are more likely to be affected than females. While there is no cure for G6PD deficiency, avoiding triggers and managing symptoms can help prevent complications.

Pyruvate is a negatively charged ion or group of atoms, called anion, with the chemical formula C3H3O3-. It is formed from the decomposition of glucose and other sugars in the process of cellular respiration. Pyruvate plays a crucial role in the metabolic pathways that generate energy for cells.

In the cytoplasm, pyruvate is produced through glycolysis, where one molecule of glucose is broken down into two molecules of pyruvate, releasing energy and producing ATP (adenosine triphosphate) and NADH (reduced nicotinamide adenine dinucleotide).

In the mitochondria, pyruvate can be further metabolized through the citric acid cycle (also known as the Krebs cycle) to produce more ATP. The process involves the conversion of pyruvate into acetyl-CoA, which then enters the citric acid cycle and undergoes a series of reactions that generate energy in the form of ATP, NADH, and FADH2 (reduced flavin adenine dinucleotide).

Overall, pyruvate is an important intermediate in cellular respiration and plays a central role in the production of energy for cells.

Acetates, in a medical context, most commonly refer to compounds that contain the acetate group, which is an functional group consisting of a carbon atom bonded to two hydrogen atoms and an oxygen atom (-COO-). An example of an acetate is sodium acetate (CH3COONa), which is a salt formed from acetic acid (CH3COOH) and is often used as a buffering agent in medical solutions.

Acetates can also refer to a group of medications that contain acetate as an active ingredient, such as magnesium acetate, which is used as a laxative, or calcium acetate, which is used to treat high levels of phosphate in the blood.

In addition, acetates can also refer to a process called acetylation, which is the addition of an acetyl group (-COCH3) to a molecule. This process can be important in the metabolism and regulation of various substances within the body.

Metabolomics is a branch of "omics" sciences that deals with the comprehensive and quantitative analysis of all metabolites, which are the small molecule intermediates and products of metabolism, in a biological sample. It involves the identification and measurement of these metabolites using various analytical techniques such as mass spectrometry and nuclear magnetic resonance spectroscopy. The resulting data provides a functional readout of the physiological state of an organism, tissue or cell, and can be used to identify biomarkers of disease, understand drug action and toxicity, and reveal new insights into metabolic pathways and regulatory networks.

Hexoses are simple sugars (monosaccharides) that contain six carbon atoms. The most common hexoses include glucose, fructose, and galactose. These sugars play important roles in various biological processes, such as serving as energy sources or forming complex carbohydrates like starch and cellulose. Hexoses are essential for the structure and function of living organisms, including humans.

Dehydroepiandrosterone (DHEA) is a steroid hormone produced by the adrenal glands. It serves as a precursor to other hormones, including androgens such as testosterone and estrogens such as estradiol. DHEA levels typically peak during early adulthood and then gradually decline with age.

DHEA has been studied for its potential effects on various health conditions, including aging, cognitive function, sexual dysfunction, and certain chronic diseases. However, the evidence supporting its use for these purposes is generally limited and inconclusive. As with any supplement or medication, it's important to consult with a healthcare provider before taking DHEA to ensure safety and effectiveness.

Lactates, also known as lactic acid, are compounds that are produced by muscles during intense exercise or other conditions of low oxygen supply. They are formed from the breakdown of glucose in the absence of adequate oxygen to complete the full process of cellular respiration. This results in the production of lactate and a hydrogen ion, which can lead to a decrease in pH and muscle fatigue.

In a medical context, lactates may be measured in the blood as an indicator of tissue oxygenation and metabolic status. Elevated levels of lactate in the blood, known as lactic acidosis, can indicate poor tissue perfusion or hypoxia, and may be seen in conditions such as sepsis, cardiac arrest, and severe shock. It is important to note that lactates are not the primary cause of acidemia (low pH) in lactic acidosis, but rather a marker of the underlying process.

Carbon radioisotopes are radioactive isotopes of carbon, which is an naturally occurring chemical element with the atomic number 6. The most common and stable isotope of carbon is carbon-12 (^12C), but there are also several radioactive isotopes, including carbon-11 (^11C), carbon-14 (^14C), and carbon-13 (^13C). These radioisotopes have different numbers of neutrons in their nuclei, which makes them unstable and causes them to emit radiation.

Carbon-11 has a half-life of about 20 minutes and is used in medical imaging techniques such as positron emission tomography (PET) scans. It is produced by bombarding nitrogen-14 with protons in a cyclotron.

Carbon-14, also known as radiocarbon, has a half-life of about 5730 years and is used in archaeology and geology to date organic materials. It is produced naturally in the atmosphere by cosmic rays.

Carbon-13 is stable and has a natural abundance of about 1.1% in carbon. It is not radioactive, but it can be used as a tracer in medical research and in the study of metabolic processes.

Gluconeogenesis is a metabolic pathway that occurs in the liver, kidneys, and to a lesser extent in the small intestine. It involves the synthesis of glucose from non-carbohydrate precursors such as lactate, pyruvate, glycerol, and certain amino acids. This process becomes particularly important during periods of fasting or starvation when glucose levels in the body begin to drop, and there is limited carbohydrate intake to replenish them.

Gluconeogenesis helps maintain blood glucose homeostasis by providing an alternative source of glucose for use by various tissues, especially the brain, which relies heavily on glucose as its primary energy source. It is a complex process that involves several enzymatic steps, many of which are regulated to ensure an adequate supply of glucose while preventing excessive production, which could lead to hyperglycemia.

Corynebacterium is a genus of Gram-positive, rod-shaped bacteria that are commonly found on the skin and mucous membranes of humans and animals. Some species of Corynebacterium can cause disease in humans, including C. diphtheriae, which causes diphtheria, and C. jeikeium, which can cause various types of infections in immunocompromised individuals. Other species are part of the normal flora and are not typically pathogenic. The bacteria are characterized by their irregular, club-shaped appearance and their ability to form characteristic arrangements called palisades. They are facultative anaerobes, meaning they can grow in the presence or absence of oxygen.

Phosphofructokinase-1 (PFK-1) is a rate-limiting enzyme in the glycolytic pathway, which is the metabolic pathway that converts glucose into pyruvate, producing ATP and NADH as energy currency for the cell. PFK-1 plays a crucial role in regulating the rate of glycolysis by catalyzing the phosphorylation of fructose-6-phosphate to fructose-1,6-bisphosphate, using ATP as the phosphate donor.

PFK-1 is allosterically regulated by various metabolites, such as AMP, ADP, and ATP, which act as positive or negative effectors of the enzyme's activity. For example, an increase in the intracellular concentration of AMP or ADP can activate PFK-1, promoting glycolysis and energy production, while an increase in ATP levels can inhibit the enzyme's activity, conserving glucose for use under conditions of low energy demand.

Deficiencies in PFK-1 can lead to a rare genetic disorder called Tarui's disease or glycogen storage disease type VII, which is characterized by exercise intolerance, muscle cramps, and myoglobinuria (the presence of myoglobin in the urine due to muscle damage).

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Biological models, also known as physiological models or organismal models, are simplified representations of biological systems, processes, or mechanisms that are used to understand and explain the underlying principles and relationships. These models can be theoretical (conceptual or mathematical) or physical (such as anatomical models, cell cultures, or animal models). They are widely used in biomedical research to study various phenomena, including disease pathophysiology, drug action, and therapeutic interventions.

Examples of biological models include:

1. Mathematical models: These use mathematical equations and formulas to describe complex biological systems or processes, such as population dynamics, metabolic pathways, or gene regulation networks. They can help predict the behavior of these systems under different conditions and test hypotheses about their underlying mechanisms.
2. Cell cultures: These are collections of cells grown in a controlled environment, typically in a laboratory dish or flask. They can be used to study cellular processes, such as signal transduction, gene expression, or metabolism, and to test the effects of drugs or other treatments on these processes.
3. Animal models: These are living organisms, usually vertebrates like mice, rats, or non-human primates, that are used to study various aspects of human biology and disease. They can provide valuable insights into the pathophysiology of diseases, the mechanisms of drug action, and the safety and efficacy of new therapies.
4. Anatomical models: These are physical representations of biological structures or systems, such as plastic models of organs or tissues, that can be used for educational purposes or to plan surgical procedures. They can also serve as a basis for developing more sophisticated models, such as computer simulations or 3D-printed replicas.

Overall, biological models play a crucial role in advancing our understanding of biology and medicine, helping to identify new targets for therapeutic intervention, develop novel drugs and treatments, and improve human health.

Androsterone is a weak androgen and an endogenous steroid hormone. It's produced in the liver from dehydroepiandrosterone (DHEA) and is converted into androstenedione, another weak androgen. Androsterone is excreted in urine as a major metabolite of testosterone. It plays a role in male sexual development and function, although its effects are much weaker than those of testosterone. In clinical contexts, androsterone levels may be measured to help diagnose certain hormonal disorders or to monitor hormone therapy.

Pyruvate kinase is an enzyme that plays a crucial role in the final step of glycolysis, a process by which glucose is broken down to produce energy in the form of ATP (adenosine triphosphate). Specifically, pyruvate kinase catalyzes the transfer of a phosphate group from phosphoenolpyruvate (PEP) to adenosine diphosphate (ADP), resulting in the formation of pyruvate and ATP.

There are several isoforms of pyruvate kinase found in different tissues, including the liver, muscle, and brain. The type found in red blood cells is known as PK-RBC or PK-M2. Deficiencies in pyruvate kinase can lead to a genetic disorder called pyruvate kinase deficiency, which can result in hemolytic anemia due to the premature destruction of red blood cells.

Fatty acid synthase (FAS) is a multi-enzyme complex that plays a crucial role in the synthesis of long-chain fatty acids in the body. There are two main types of FAS: type I and type II.

Type I fatty acid synthase, also known as FASN, is found primarily in the cytoplasm of cells in tissues such as the liver, adipose tissue, and lactating mammary glands. It is a large protein made up of several distinct enzymatic domains that work together to synthesize long-chain fatty acids from acetyl-CoA and malonyl-CoA.

The process of fatty acid synthesis involves a series of reactions, starting with the condensation of acetyl-CoA and malonyl-CoA to form acetoacetyl-CoA. This reaction is followed by a series of reductions, dehydrations, and another reduction to form a saturated fatty acid molecule with 16 carbons (palmitate).

Type I FAS is often upregulated in conditions associated with increased lipogenesis, such as obesity, metabolic syndrome, and certain types of cancer. Inhibiting FAS has been explored as a potential therapeutic strategy for treating these conditions.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an enzyme that plays a crucial role in the metabolic pathway of glycolysis. Its primary function is to convert glyceraldehyde-3-phosphate (a triose sugar phosphate) into D-glycerate 1,3-bisphosphate, while also converting nicotinamide adenine dinucleotide (NAD+) into its reduced form NADH. This reaction is essential for the production of energy in the form of adenosine triphosphate (ATP) during cellular respiration. GAPDH has also been implicated in various non-metabolic processes, including DNA replication, repair, and transcription regulation, due to its ability to interact with different proteins and nucleic acids.

Glutathione is a tripeptide composed of three amino acids: cysteine, glutamic acid, and glycine. It is a vital antioxidant that plays an essential role in maintaining cellular health and function. Glutathione helps protect cells from oxidative stress by neutralizing free radicals, which are unstable molecules that can damage cells and contribute to aging and diseases such as cancer, heart disease, and dementia. It also supports the immune system, detoxifies harmful substances, and regulates various cellular processes, including DNA synthesis and repair.

Glutathione is found in every cell of the body, with particularly high concentrations in the liver, lungs, and eyes. The body can produce its own glutathione, but levels may decline with age, illness, or exposure to toxins. As such, maintaining optimal glutathione levels through diet, supplementation, or other means is essential for overall health and well-being.

NAD (Nicotinamide Adenine Dinucleotide) is a coenzyme found in all living cells. It plays an essential role in cellular metabolism, particularly in redox reactions, where it acts as an electron carrier. NAD exists in two forms: NAD+, which accepts electrons and becomes reduced to NADH. This pairing of NAD+/NADH is involved in many fundamental biological processes such as generating energy in the form of ATP during cellular respiration, and serving as a critical cofactor for various enzymes that regulate cellular functions like DNA repair, gene expression, and cell death.

Maintaining optimal levels of NAD+/NADH is crucial for overall health and longevity, as it declines with age and in certain disease states. Therefore, strategies to boost NAD+ levels are being actively researched for their potential therapeutic benefits in various conditions such as aging, neurodegenerative disorders, and metabolic diseases.

Fructose-1,6-bisphosphate (also known as fructose 1,6-diphosphate or Fru-1,6-BP) is the chemical compound that plays a crucial role in cellular respiration and glucose metabolism. It is not accurate to refer to "fructosephosphates" as a medical term, but fructose-1-phosphate and fructose-1,6-bisphosphate are important fructose phosphates with specific functions in the body.

Fructose-1-phosphate is an intermediate metabolite formed during the breakdown of fructose in the liver, while fructose-1,6-bisphosphate is a key regulator of glycolysis, the process by which glucose is broken down to produce energy in the form of ATP. Fructose-1,6-bisphosphate allosterically regulates the enzyme phosphofructokinase, which is the rate-limiting step in glycolysis, and its levels are tightly controlled to maintain proper glucose metabolism. Dysregulation of fructose metabolism has been implicated in various metabolic disorders, including insulin resistance, type 2 diabetes, and nonalcoholic fatty liver disease (NAFLD).

Magnetic Resonance Spectroscopy (MRS) is a non-invasive diagnostic technique that provides information about the biochemical composition of tissues, including their metabolic state. It is often used in conjunction with Magnetic Resonance Imaging (MRI) to analyze various metabolites within body tissues, such as the brain, heart, liver, and muscles.

During MRS, a strong magnetic field, radio waves, and a computer are used to produce detailed images and data about the concentration of specific metabolites in the targeted tissue or organ. This technique can help detect abnormalities related to energy metabolism, neurotransmitter levels, pH balance, and other biochemical processes, which can be useful for diagnosing and monitoring various medical conditions, including cancer, neurological disorders, and metabolic diseases.

There are different types of MRS, such as Proton (^1^H) MRS, Phosphorus-31 (^31^P) MRS, and Carbon-13 (^13^C) MRS, each focusing on specific elements or metabolites within the body. The choice of MRS technique depends on the clinical question being addressed and the type of information needed for diagnosis or monitoring purposes.

The Radioisotope Dilution Technique is a method used in nuclear medicine to measure the volume and flow rate of a particular fluid in the body. It involves introducing a known amount of a radioactive isotope, or radioisotope, into the fluid, such as blood. The isotope mixes with the fluid, and samples are then taken from the fluid at various time points.

By measuring the concentration of the radioisotope in each sample, it is possible to calculate the total volume of the fluid based on the amount of the isotope introduced and the dilution factor. The flow rate can also be calculated by measuring the concentration of the isotope over time and using the formula:

Flow rate = Volume/Time

This technique is commonly used in medical research and clinical settings to measure cardiac output, cerebral blood flow, and renal function, among other applications. It is a safe and reliable method that has been widely used for many years. However, it does require the use of radioactive materials and specialized equipment, so it should only be performed by trained medical professionals in appropriate facilities.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

Glucose 1-Dehydrogenase (G1DH) is an enzyme that catalyzes the oxidation of β-D-glucose into D-glucono-1,5-lactone and reduces the cofactor NAD+ into NADH. This reaction plays a role in various biological processes, including glucose sensing and detoxification of reactive carbonyl species. G1DH is found in many organisms, including humans, and has several isoforms with different properties and functions.

Genetic engineering, also known as genetic modification, is a scientific process where the DNA or genetic material of an organism is manipulated to bring about a change in its characteristics. This is typically done by inserting specific genes into the organism's genome using various molecular biology techniques. These new genes may come from the same species (cisgenesis) or a different species (transgenesis). The goal is to produce a desired trait, such as resistance to pests, improved nutritional content, or increased productivity. It's widely used in research, medicine, and agriculture. However, it's important to note that the use of genetically engineered organisms can raise ethical, environmental, and health concerns.

Lactic acid, also known as 2-hydroxypropanoic acid, is a chemical compound that plays a significant role in various biological processes. In the context of medicine and biochemistry, lactic acid is primarily discussed in relation to muscle metabolism and cellular energy production. Here's a medical definition for lactic acid:

Lactic acid (LA): A carboxylic acid with the molecular formula C3H6O3 that plays a crucial role in anaerobic respiration, particularly during strenuous exercise or conditions of reduced oxygen availability. It is formed through the conversion of pyruvate, catalyzed by the enzyme lactate dehydrogenase (LDH), when there is insufficient oxygen to complete the final step of cellular respiration in the Krebs cycle. The accumulation of lactic acid can lead to acidosis and muscle fatigue. Additionally, lactic acid serves as a vital intermediary in various metabolic pathways and is involved in the production of glucose through gluconeogenesis in the liver.

Adenine nucleotides are molecules that consist of a nitrogenous base called adenine, which is linked to a sugar molecule (ribose in the case of adenosine monophosphate or AMP, and deoxyribose in the case of adenosine diphosphate or ADP and adenosine triphosphate or ATP) and one, two, or three phosphate groups. These molecules play a crucial role in energy transfer and metabolism within cells.

AMP contains one phosphate group, while ADP contains two phosphate groups, and ATP contains three phosphate groups. When a phosphate group is removed from ATP, energy is released, which can be used to power various cellular processes such as muscle contraction, nerve impulse transmission, and protein synthesis. The reverse reaction, in which a phosphate group is added back to ADP or AMP to form ATP, requires energy input and often involves the breakdown of nutrients such as glucose or fatty acids.

In addition to their role in energy metabolism, adenine nucleotides also serve as precursors for other important molecules, including DNA and RNA, coenzymes, and signaling molecules.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Oxidative stress is defined as an imbalance between the production of reactive oxygen species (free radicals) and the body's ability to detoxify them or repair the damage they cause. This imbalance can lead to cellular damage, oxidation of proteins, lipids, and DNA, disruption of cellular functions, and activation of inflammatory responses. Prolonged or excessive oxidative stress has been linked to various health conditions, including cancer, cardiovascular diseases, neurodegenerative disorders, and aging-related diseases.

Culture media is a substance that is used to support the growth of microorganisms or cells in an artificial environment, such as a petri dish or test tube. It typically contains nutrients and other factors that are necessary for the growth and survival of the organisms being cultured. There are many different types of culture media, each with its own specific formulation and intended use. Some common examples include blood agar, which is used to culture bacteria; Sabouraud dextrose agar, which is used to culture fungi; and Eagle's minimum essential medium, which is used to culture animal cells.

Glyoxylates are organic compounds that are intermediates in various metabolic pathways, including the glyoxylate cycle. The glyoxylate cycle is a modified version of the Krebs cycle (also known as the citric acid cycle) and is found in plants, bacteria, and some fungi.

Glyoxylates are formed from the breakdown of certain amino acids or from the oxidation of one-carbon units. They can be converted into glycine, an important amino acid involved in various metabolic processes. In the glyoxylate cycle, glyoxylates are combined with acetyl-CoA to form malate and succinate, which can then be used to synthesize glucose or other organic compounds.

Abnormal accumulation of glyoxylates in the body can lead to the formation of calcium oxalate crystals, which can cause kidney stones and other health problems. Certain genetic disorders, such as primary hyperoxaluria, can result in overproduction of glyoxylates and increased risk of kidney stone formation.

Calcium phosphates are a group of minerals that are important components of bones and teeth. They are also found in some foods and are used in dietary supplements and medical applications. Chemically, calcium phosphates are salts of calcium and phosphoric acid, and they exist in various forms, including hydroxyapatite, which is the primary mineral component of bone tissue. Other forms of calcium phosphates include monocalcium phosphate, dicalcium phosphate, and tricalcium phosphate, which are used as food additives and dietary supplements. Calcium phosphates are important for maintaining strong bones and teeth, and they also play a role in various physiological processes, such as nerve impulse transmission and muscle contraction.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Malate Dehydrogenase (MDH) is an enzyme that plays a crucial role in the Krebs cycle, also known as the citric acid cycle or tricarboxylic acid (TCA) cycle. It catalyzes the reversible oxidation of malate to oxaloacetate, while simultaneously reducing NAD+ to NADH. This reaction is essential for energy production in the form of ATP and NADH within the cell.

There are two main types of Malate Dehydrogenase:

1. NAD-dependent Malate Dehydrogenase (MDH1): Found primarily in the cytoplasm, this isoform plays a role in the malate-aspartate shuttle, which helps transfer reducing equivalents between the cytoplasm and mitochondria.
2. FAD-dependent Malate Dehydrogenase (MDH2): Located within the mitochondrial matrix, this isoform is involved in the Krebs cycle for energy production.

Abnormal levels of Malate Dehydrogenase enzyme can be indicative of certain medical conditions or diseases, such as myocardial infarction (heart attack), muscle damage, or various types of cancer. Therefore, MDH enzyme activity is often assessed in diagnostic tests to help identify and monitor these health issues.

Biomass is defined in the medical field as a renewable energy source derived from organic materials, primarily plant matter, that can be burned or converted into fuel. This includes materials such as wood, agricultural waste, and even methane gas produced by landfills. Biomass is often used as a source of heat, electricity, or transportation fuels, and its use can help reduce greenhouse gas emissions and dependence on fossil fuels.

In the context of human health, biomass burning can have both positive and negative impacts. On one hand, biomass can provide a source of heat and energy for cooking and heating, which can improve living standards and reduce exposure to harmful pollutants from traditional cooking methods such as open fires. On the other hand, biomass burning can also produce air pollution, including particulate matter and toxic chemicals, that can have negative effects on respiratory health and contribute to climate change.

Therefore, while biomass has the potential to be a sustainable and low-carbon source of energy, it is important to consider the potential health and environmental impacts of its use and implement appropriate measures to minimize any negative effects.

Isotope labeling is a scientific technique used in the field of medicine, particularly in molecular biology, chemistry, and pharmacology. It involves replacing one or more atoms in a molecule with a radioactive or stable isotope of the same element. This modified molecule can then be traced and analyzed to study its structure, function, metabolism, or interaction with other molecules within biological systems.

Radioisotope labeling uses unstable radioactive isotopes that emit radiation, allowing for detection and quantification of the labeled molecule using various imaging techniques, such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT). This approach is particularly useful in tracking the distribution and metabolism of drugs, hormones, or other biomolecules in living organisms.

Stable isotope labeling, on the other hand, employs non-radioactive isotopes that do not emit radiation. These isotopes have different atomic masses compared to their natural counterparts and can be detected using mass spectrometry. Stable isotope labeling is often used in metabolic studies, protein turnover analysis, or for identifying the origin of specific molecules within complex biological samples.

In summary, isotope labeling is a versatile tool in medical research that enables researchers to investigate various aspects of molecular behavior and interactions within biological systems.

'Corynebacterium glutamicum' is a species of Gram-positive, rod-shaped bacteria that are commonly found in the environment, particularly in soil and water. It is a facultative anaerobe, which means it can grow with or without oxygen. The bacterium is non-pathogenic and has been widely studied and used in biotechnology due to its ability to produce various amino acids and other industrially relevant compounds.

The name 'Corynebacterium glutamicum' comes from its discovery as a bacterium that can ferment the amino acid glutamate, which is why it has been extensively used in the industrial production of L-glutamate, an important ingredient in many food products and feed additives.

In recent years, 'Corynebacterium glutamicum' has also gained attention as a potential platform organism for the production of various biofuels and biochemicals, including alcohols, organic acids, and hydrocarbons. Its genetic tractability and ability to utilize a wide range of carbon sources make it an attractive candidate for biotechnological applications.

Anaerobiosis is a state in which an organism or a portion of an organism is able to live and grow in the absence of molecular oxygen (O2). In biological contexts, "anaerobe" refers to any organism that does not require oxygen for growth, and "aerobe" refers to an organism that does require oxygen for growth.

There are two types of anaerobes: obligate anaerobes, which cannot tolerate the presence of oxygen and will die if exposed to it; and facultative anaerobes, which can grow with or without oxygen but prefer to grow in its absence. Some organisms are able to switch between aerobic and anaerobic metabolism depending on the availability of oxygen, a process known as "facultative anaerobiosis."

Anaerobic respiration is a type of metabolic process that occurs in the absence of molecular oxygen. In this process, organisms use alternative electron acceptors other than oxygen to generate energy through the transfer of electrons during cellular respiration. Examples of alternative electron acceptors include nitrate, sulfate, and carbon dioxide.

Anaerobic metabolism is less efficient than aerobic metabolism in terms of energy production, but it allows organisms to survive in environments where oxygen is not available or is toxic. Anaerobic bacteria are important decomposers in many ecosystems, breaking down organic matter and releasing nutrients back into the environment. In the human body, anaerobic bacteria can cause infections and other health problems if they proliferate in areas with low oxygen levels, such as the mouth, intestines, or deep tissue wounds.

Glutathione reductase (GR) is an enzyme that plays a crucial role in maintaining the cellular redox state. The primary function of GR is to reduce oxidized glutathione (GSSG) to its reduced form (GSH), which is an essential intracellular antioxidant. This enzyme utilizes nicotinamide adenine dinucleotide phosphate (NADPH) as a reducing agent in the reaction, converting it to NADP+. The medical definition of Glutathione Reductase is:

Glutathione reductase (GSR; EC 1.8.1.7) is a homodimeric flavoprotein that catalyzes the reduction of oxidized glutathione (GSSG) to reduced glutathione (GSH) in the presence of NADPH as a cofactor. This enzyme is essential for maintaining the cellular redox balance and protecting cells from oxidative stress by regenerating the active form of glutathione, a vital antioxidant and detoxifying agent.

I'm sorry for any confusion, but "Hemiterpenes" is not a recognized term in medical or biochemistry terminology. The term "terpene" does refer to a large class of naturally occurring organic hydrocarbons, which are synthesized in various plants and animals. They are built from repeating units of isoprene (a five-carbon molecule), and can be further classified into monoterpenes (two isoprene units), sesquiterpenes (three isoprene units), diterpenes (four isoprene units), and so on.

However, the prefix "hemi-" means "half," which doesn't have a clear application in this context. It's possible there may be a misunderstanding or a typo in your question. If you meant to ask about a specific type of compound or a concept related to terpenes, please provide more context so I can give a more accurate answer.

"Saccharomyces cerevisiae" is not typically considered a medical term, but it is a scientific name used in the field of microbiology. It refers to a species of yeast that is commonly used in various industrial processes, such as baking and brewing. It's also widely used in scientific research due to its genetic tractability and eukaryotic cellular organization.

However, it does have some relevance to medical fields like medicine and nutrition. For example, certain strains of S. cerevisiae are used as probiotics, which can provide health benefits when consumed. They may help support gut health, enhance the immune system, and even assist in the digestion of certain nutrients.

In summary, "Saccharomyces cerevisiae" is a species of yeast with various industrial and potential medical applications.

Glycogen is a complex carbohydrate that serves as the primary form of energy storage in animals, fungi, and bacteria. It is a polysaccharide consisting of long, branched chains of glucose molecules linked together by glycosidic bonds. Glycogen is stored primarily in the liver and muscles, where it can be quickly broken down to release glucose into the bloodstream during periods of fasting or increased metabolic demand.

In the liver, glycogen plays a crucial role in maintaining blood glucose levels by releasing glucose when needed, such as between meals or during exercise. In muscles, glycogen serves as an immediate energy source for muscle contractions during intense physical activity. The ability to store and mobilize glycogen is essential for the proper functioning of various physiological processes, including athletic performance, glucose homeostasis, and overall metabolic health.

Aerobiosis is the process of living, growing, and functioning in the presence of oxygen. It refers to the metabolic processes that require oxygen to break down nutrients and produce energy in cells. This is in contrast to anaerobiosis, which is the ability to live and grow in the absence of oxygen.

In medical terms, aerobiosis is often used to describe the growth of microorganisms, such as bacteria and fungi, that require oxygen to survive and multiply. These organisms are called aerobic organisms, and they play an important role in many biological processes, including decomposition and waste breakdown.

However, some microorganisms are unable to grow in the presence of oxygen and are instead restricted to environments where oxygen is absent or limited. These organisms are called anaerobic organisms, and their growth and metabolism are referred to as anaerobiosis.

Glycerol, also known as glycerine or glycerin, is a simple polyol (a sugar alcohol) with a sweet taste and a thick, syrupy consistency. It is a colorless, odorless, viscous liquid that is slightly soluble in water and freely miscible with ethanol and ether.

In the medical field, glycerol is often used as a medication or supplement. It can be used as a laxative to treat constipation, as a source of calories and energy for people who cannot eat by mouth, and as a way to prevent dehydration in people with certain medical conditions.

Glycerol is also used in the production of various medical products, such as medications, skin care products, and vaccines. It acts as a humectant, which means it helps to keep things moist, and it can also be used as a solvent or preservative.

In addition to its medical uses, glycerol is also widely used in the food industry as a sweetener, thickening agent, and moisture-retaining agent. It is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA).

Trehalose is a type of disaccharide, which is a sugar made up of two monosaccharides. It consists of two glucose molecules joined together in a way that makes it more stable and resistant to breakdown by enzymes and heat. This property allows trehalose to be used as a protectant for biological materials during freeze-drying and storage, as well as a food additive as a sweetener and preservative.

Trehalose is found naturally in some plants, fungi, insects, and microorganisms, where it serves as a source of energy and protection against environmental stresses such as drought, heat, and cold. In recent years, there has been interest in the potential therapeutic uses of trehalose for various medical conditions, including neurodegenerative diseases, diabetes, and cancer.

Medically speaking, trehalose may be used in some pharmaceutical formulations as an excipient or stabilizer, and it is also being investigated as a potential therapeutic agent for various diseases. However, its use as a medical treatment is still not widely established, and further research is needed to determine its safety and efficacy.

Fructose-bisphosphate aldolase is a crucial enzyme in the glycolytic pathway, which is a metabolic process that breaks down glucose to produce energy. This enzyme catalyzes the conversion of fructose-1,6-bisphosphate into two triose sugars: dihydroxyacetone phosphate and glyceraldehyde-3-phosphate.

There are two main types of aldolase isoenzymes in humans, classified as aldolase A (or muscle type) and aldolase B (or liver type). Fructose-bisphosphate aldolase refers specifically to aldolase A, which is primarily found in the muscles, brain, and red blood cells. Aldolase B, on the other hand, is predominantly found in the liver, kidney, and small intestine.

Deficiency or dysfunction of fructose-bisphosphate aldolase can lead to metabolic disorders, such as hereditary fructose intolerance, which results from a deficiency in another enzyme called aldolase B. However, it is essential to note that the term "fructose-bisphosphate aldolase" typically refers to aldolase A and not aldolase B.

Starvation is a severe form of malnutrition, characterized by insufficient intake of calories and nutrients to meet the body's energy requirements. This leads to a catabolic state where the body begins to break down its own tissues for energy, resulting in significant weight loss, muscle wasting, and weakness. Prolonged starvation can also lead to serious medical complications such as organ failure, electrolyte imbalances, and even death. It is typically caused by a lack of access to food due to poverty, famine, or other social or economic factors, but can also be a result of severe eating disorders such as anorexia nervosa.

Acetyl Coenzyme A, often abbreviated as Acetyl-CoA, is a key molecule in metabolism, particularly in the breakdown and oxidation of carbohydrates, fats, and proteins to produce energy. It is a coenzyme that plays a central role in the cellular process of transforming the energy stored in the chemical bonds of nutrients into a form that the cell can use.

Acetyl-CoA consists of an acetyl group (two carbon atoms) linked to coenzyme A, a complex organic molecule. This linkage is facilitated by an enzyme called acetyltransferase. Once formed, Acetyl-CoA can enter various metabolic pathways. In the citric acid cycle (also known as the Krebs cycle), Acetyl-CoA is further oxidized to release energy in the form of ATP, NADH, and FADH2, which are used in other cellular processes. Additionally, Acetyl-CoA is involved in the biosynthesis of fatty acids, cholesterol, and certain amino acids.

In summary, Acetyl Coenzyme A is a vital molecule in metabolism that connects various biochemical pathways for energy production and biosynthesis.

Glucokinase is an enzyme that plays a crucial role in regulating glucose metabolism. It is primarily found in the liver, pancreas, and brain. In the pancreas, glucokinase helps to trigger the release of insulin in response to rising blood glucose levels. In the liver, it plays a key role in controlling glucose storage and production.

Glucokinase has a unique property among hexokinases (enzymes that phosphorylate six-carbon sugars) in that it is not inhibited by its product, glucose-6-phosphate. This allows it to continue functioning even when glucose levels are high, making it an important regulator of glucose metabolism.

Defects in the gene that codes for glucokinase can lead to several types of inherited diabetes and other metabolic disorders.

Ethanol is the medical term for pure alcohol, which is a colorless, clear, volatile, flammable liquid with a characteristic odor and burning taste. It is the type of alcohol that is found in alcoholic beverages and is produced by the fermentation of sugars by yeasts.

In the medical field, ethanol is used as an antiseptic and disinfectant, and it is also used as a solvent for various medicinal preparations. It has central nervous system depressant properties and is sometimes used as a sedative or to induce sleep. However, excessive consumption of ethanol can lead to alcohol intoxication, which can cause a range of negative health effects, including impaired judgment, coordination, and memory, as well as an increased risk of accidents, injuries, and chronic diseases such as liver disease and addiction.

Adenosine Triphosphate (ATP) is a high-energy molecule that stores and transports energy within cells. It is the main source of energy for most cellular processes, including muscle contraction, nerve impulse transmission, and protein synthesis. ATP is composed of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups contain a significant amount of energy, which can be released when the bond between the second and third phosphate group is broken, resulting in the formation of adenosine diphosphate (ADP) and inorganic phosphate. This process is known as hydrolysis and can be catalyzed by various enzymes to drive a wide range of cellular functions. ATP can also be regenerated from ADP through various metabolic pathways, such as oxidative phosphorylation or substrate-level phosphorylation, allowing for the continuous supply of energy to cells.

Energy metabolism is the process by which living organisms produce and consume energy to maintain life. It involves a series of chemical reactions that convert nutrients from food, such as carbohydrates, fats, and proteins, into energy in the form of adenosine triphosphate (ATP).

The process of energy metabolism can be divided into two main categories: catabolism and anabolism. Catabolism is the breakdown of nutrients to release energy, while anabolism is the synthesis of complex molecules from simpler ones using energy.

There are three main stages of energy metabolism: glycolysis, the citric acid cycle (also known as the Krebs cycle), and oxidative phosphorylation. Glycolysis occurs in the cytoplasm of the cell and involves the breakdown of glucose into pyruvate, producing a small amount of ATP and nicotinamide adenine dinucleotide (NADH). The citric acid cycle takes place in the mitochondria and involves the further breakdown of pyruvate to produce more ATP, NADH, and carbon dioxide. Oxidative phosphorylation is the final stage of energy metabolism and occurs in the inner mitochondrial membrane. It involves the transfer of electrons from NADH and other electron carriers to oxygen, which generates a proton gradient across the membrane. This gradient drives the synthesis of ATP, producing the majority of the cell's energy.

Overall, energy metabolism is a complex and essential process that allows organisms to grow, reproduce, and maintain their bodily functions. Disruptions in energy metabolism can lead to various diseases, including diabetes, obesity, and neurodegenerative disorders.

Ketosis is a metabolic state characterized by elevated levels of ketone bodies in the blood or urine. Ketone bodies are molecules produced from fatty acids during the breakdown of fats for energy, particularly when carbohydrate intake is low. This process occurs naturally in our body, and it's a part of normal metabolism. However, ketosis becomes significant under certain conditions such as:

1. Diabetic ketoacidosis (DKA): A serious complication in people with diabetes, typically type 1 diabetes, which happens when there are extremely high levels of ketones and blood sugar due to insulin deficiency or a severe infection. DKA is a medical emergency that requires immediate treatment.
2. Starvation or fasting: When the body doesn't receive enough carbohydrates from food, it starts breaking down fats for energy, leading to ketosis. This can occur during prolonged fasting or starvation.
3. Low-carbohydrate diets (LCDs) or ketogenic diets: Diets that restrict carbohydrate intake and emphasize high fat and protein consumption can induce a state of nutritional ketosis, where ketone bodies are used as the primary energy source. This type of ketosis is not harmful and can be beneficial for weight loss and managing certain medical conditions like epilepsy.

It's important to note that there is a difference between diabetic ketoacidosis (DKA), which is a dangerous condition, and nutritional ketosis, which is a normal metabolic process and can be achieved through dietary means without negative health consequences for most individuals.

Gene deletion is a type of mutation where a segment of DNA, containing one or more genes, is permanently lost or removed from a chromosome. This can occur due to various genetic mechanisms such as homologous recombination, non-homologous end joining, or other types of genomic rearrangements.

The deletion of a gene can have varying effects on the organism, depending on the function of the deleted gene and its importance for normal physiological processes. If the deleted gene is essential for survival, the deletion may result in embryonic lethality or developmental abnormalities. However, if the gene is non-essential or has redundant functions, the deletion may not have any noticeable effects on the organism's phenotype.

Gene deletions can also be used as a tool in genetic research to study the function of specific genes and their role in various biological processes. For example, researchers may use gene deletion techniques to create genetically modified animal models to investigate the impact of gene deletion on disease progression or development.

Gene expression regulation in bacteria refers to the complex cellular processes that control the production of proteins from specific genes. This regulation allows bacteria to adapt to changing environmental conditions and ensure the appropriate amount of protein is produced at the right time.

Bacteria have a variety of mechanisms for regulating gene expression, including:

1. Operon structure: Many bacterial genes are organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule. The expression of these genes can be coordinately regulated by controlling the transcription of the entire operon.
2. Promoter regulation: Transcription is initiated at promoter regions upstream of the gene or operon. Bacteria have regulatory proteins called sigma factors that bind to the promoter and recruit RNA polymerase, the enzyme responsible for transcribing DNA into RNA. The binding of sigma factors can be influenced by environmental signals, allowing for regulation of transcription.
3. Attenuation: Some operons have regulatory regions called attenuators that control transcription termination. These regions contain hairpin structures that can form in the mRNA and cause transcription to stop prematurely. The formation of these hairpins is influenced by the concentration of specific metabolites, allowing for regulation of gene expression based on the availability of those metabolites.
4. Riboswitches: Some bacterial mRNAs contain regulatory elements called riboswitches that bind small molecules directly. When a small molecule binds to the riboswitch, it changes conformation and affects transcription or translation of the associated gene.
5. CRISPR-Cas systems: Bacteria use CRISPR-Cas systems for adaptive immunity against viruses and plasmids. These systems incorporate short sequences from foreign DNA into their own genome, which can then be used to recognize and cleave similar sequences in invading genetic elements.

Overall, gene expression regulation in bacteria is a complex process that allows them to respond quickly and efficiently to changing environmental conditions. Understanding these regulatory mechanisms can provide insights into bacterial physiology and help inform strategies for controlling bacterial growth and behavior.

Gas Chromatography-Mass Spectrometry (GC-MS) is a powerful analytical technique that combines the separating power of gas chromatography with the identification capabilities of mass spectrometry. This method is used to separate, identify, and quantify different components in complex mixtures.

In GC-MS, the mixture is first vaporized and carried through a long, narrow column by an inert gas (carrier gas). The various components in the mixture interact differently with the stationary phase inside the column, leading to their separation based on their partition coefficients between the mobile and stationary phases. As each component elutes from the column, it is then introduced into the mass spectrometer for analysis.

The mass spectrometer ionizes the sample, breaks it down into smaller fragments, and measures the mass-to-charge ratio of these fragments. This information is used to generate a mass spectrum, which serves as a unique "fingerprint" for each compound. By comparing the generated mass spectra with reference libraries or known standards, analysts can identify and quantify the components present in the original mixture.

GC-MS has wide applications in various fields such as forensics, environmental analysis, drug testing, and research laboratories due to its high sensitivity, specificity, and ability to analyze volatile and semi-volatile compounds.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Phosphotransferases are a group of enzymes that catalyze the transfer of a phosphate group from a donor molecule to an acceptor molecule. This reaction is essential for various cellular processes, including energy metabolism, signal transduction, and biosynthesis.

The systematic name for this group of enzymes is phosphotransferase, which is derived from the general reaction they catalyze: D-donor + A-acceptor = D-donor minus phosphate + A-phosphate. The donor molecule can be a variety of compounds, such as ATP or a phosphorylated protein, while the acceptor molecule is typically a compound that becomes phosphorylated during the reaction.

Phosphotransferases are classified into several subgroups based on the type of donor and acceptor molecules they act upon. For example, kinases are a subgroup of phosphotransferases that transfer a phosphate group from ATP to a protein or other organic compound. Phosphatases, another subgroup, remove phosphate groups from molecules by transferring them to water.

Overall, phosphotransferases play a critical role in regulating many cellular functions and are important targets for drug development in various diseases, including cancer and neurological disorders.

Carboxylic ester hydrolases are a class of enzymes that catalyze the hydrolysis of ester bonds in carboxylic acid esters, producing alcohols and carboxylates. This group includes several subclasses of enzymes such as esterases, lipases, and thioesterases. These enzymes play important roles in various biological processes, including metabolism, detoxification, and signal transduction. They are widely used in industrial applications, such as the production of biodiesel, pharmaceuticals, and food ingredients.

Deoxyglucose is a glucose molecule that has had one oxygen atom removed, resulting in the absence of a hydroxyl group (-OH) at the 2' position of the carbon chain. It is used in research and medical settings as a metabolic tracer to study glucose uptake and metabolism in cells and organisms.

Deoxyglucose can be taken up by cells through glucose transporters, but it cannot be further metabolized by glycolysis or other glucose-utilizing pathways. This leads to the accumulation of deoxyglucose within the cell, which can interfere with normal cellular processes and cause toxicity in high concentrations.

In medical research, deoxyglucose is sometimes labeled with radioactive isotopes such as carbon-14 or fluorine-18 to create radiolabeled deoxyglucose (FDG), which can be used in positron emission tomography (PET) scans to visualize and measure glucose uptake in tissues. This technique is commonly used in cancer imaging, as tumors often have increased glucose metabolism compared to normal tissue.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Hydrogen peroxide (H2O2) is a colorless, odorless, clear liquid with a slightly sweet taste, although drinking it is harmful and can cause poisoning. It is a weak oxidizing agent and is used as an antiseptic and a bleaching agent. In diluted form, it is used to disinfect wounds and kill bacteria and viruses on the skin; in higher concentrations, it can be used to bleach hair or remove stains from clothing. It is also used as a propellant in rocketry and in certain industrial processes. Chemically, hydrogen peroxide is composed of two hydrogen atoms and two oxygen atoms, and it is structurally similar to water (H2O), with an extra oxygen atom. This gives it its oxidizing properties, as the additional oxygen can be released and used to react with other substances.

Cytosol refers to the liquid portion of the cytoplasm found within a eukaryotic cell, excluding the organelles and structures suspended in it. It is the site of various metabolic activities and contains a variety of ions, small molecules, and enzymes. The cytosol is where many biochemical reactions take place, including glycolysis, protein synthesis, and the regulation of cellular pH. It is also where some organelles, such as ribosomes and vesicles, are located. In contrast to the cytosol, the term "cytoplasm" refers to the entire contents of a cell, including both the cytosol and the organelles suspended within it.

Glutamine is defined as a conditionally essential amino acid in humans, which means that it can be produced by the body under normal circumstances, but may become essential during certain conditions such as stress, illness, or injury. It is the most abundant free amino acid found in the blood and in the muscles of the body.

Glutamine plays a crucial role in various biological processes, including protein synthesis, energy production, and acid-base balance. It serves as an important fuel source for cells in the intestines, immune system, and skeletal muscles. Glutamine has also been shown to have potential benefits in wound healing, gut function, and immunity, particularly during times of physiological stress or illness.

In summary, glutamine is a vital amino acid that plays a critical role in maintaining the health and function of various tissues and organs in the body.

Organophosphorus compounds are a class of chemical substances that contain phosphorus bonded to organic compounds. They are used in various applications, including as plasticizers, flame retardants, pesticides (insecticides, herbicides, and nerve gases), and solvents. In medicine, they are also used in the treatment of certain conditions such as glaucoma. However, organophosphorus compounds can be toxic to humans and animals, particularly those that affect the nervous system by inhibiting acetylcholinesterase, an enzyme that breaks down the neurotransmitter acetylcholine. Exposure to these compounds can cause symptoms such as nausea, vomiting, muscle weakness, and in severe cases, respiratory failure and death.

Erythrocytes, also known as red blood cells (RBCs), are the most common type of blood cell in circulating blood in mammals. They are responsible for transporting oxygen from the lungs to the body's tissues and carbon dioxide from the tissues to the lungs.

Erythrocytes are formed in the bone marrow and have a biconcave shape, which allows them to fold and bend easily as they pass through narrow blood vessels. They do not have a nucleus or mitochondria, which makes them more flexible but also limits their ability to reproduce or repair themselves.

In humans, erythrocytes are typically disc-shaped and measure about 7 micrometers in diameter. They contain the protein hemoglobin, which binds to oxygen and gives blood its red color. The lifespan of an erythrocyte is approximately 120 days, after which it is broken down in the liver and spleen.

Abnormalities in erythrocyte count or function can lead to various medical conditions, such as anemia, polycythemia, and sickle cell disease.

Reactive Oxygen Species (ROS) are highly reactive molecules containing oxygen, including peroxides, superoxide, hydroxyl radical, and singlet oxygen. They are naturally produced as byproducts of normal cellular metabolism in the mitochondria, and can also be generated by external sources such as ionizing radiation, tobacco smoke, and air pollutants. At low or moderate concentrations, ROS play important roles in cell signaling and homeostasis, but at high concentrations, they can cause significant damage to cell structures, including lipids, proteins, and DNA, leading to oxidative stress and potential cell death.

The chemical logic behind the pentose phosphate pathway Pentose+Phosphate+Pathway at the U.S. National Library of Medicine ... The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt and the HMP Shunt) ... 3 ribulose-5-phosphate → 1 ribose-5-phosphate + 2 xylulose-5-phosphate → 2 fructose-6-phosphate + glyceraldehyde-3-phosphate ... the pentose phosphate pathway appears to have a very ancient evolutionary origin. The reactions of this pathway are mostly ...
"Pentose Phosphate Pathway". Molecular Biochemistry II Notes. The Biochemistry and Biophysics Program at Renssalaer Polytechnic ... Transaldolase, the namesake of aldehyde transferases, is an important part of the pentose phosphate pathway. The reaction it ... glyceraldehyde 3-phosphate ⇌ {\displaystyle \rightleftharpoons } erythrose 4-phosphate + fructose 6-phosphate. Transfer of acyl ... Groups that are classified as phosphate acceptors include: alcohols, carboxy groups, nitrogenous groups, and phosphate groups. ...
However, he is best known for his work in elucidating the pentose phosphate pathway. Much of his work, especially of the ... Bernard Leonard (Bernie) Horecker (1914-2010) was an American biochemist known for work on the pentose phosphate pathway, and ... Horecker, Bernard L. (2002). "The pentose phosphate pathway". J. Biol. Chem. 277 (50): 47965-47971. doi:10.1074/jbc.X200007200 ... especially those of the pentose phosphate pathway." He started his scientific career with a manometric study of succinate ...
Patra, Krushna C; Hay, Nissim (2014). "The pentose phosphate pathway and cancer". Trends in Biochemical Sciences. 39 (8): 347. ... in respiratory and photosynthetic pathways and plays a vital role in the non-oxidative branch of the pentose phosphate pathway ... The Formation of Fructose-6-Phosphate from Sedoheptulose-7-Phosphate". Journal of the American Chemical Society. 75 (8): 2021. ... Sedoheptulose 7-phosphate https://iupac.qmul.ac.uk/2carb/10.html Ogata, James N.; Kawano, Yoshihiko; Bevenue, Arthur; Casarett ...
Patra, Krushna C; Hay, Nissim (2014). "The pentose phosphate pathway and cancer". Trends in Biochemical Sciences. 39 (8): 347. ... Horecker, B. L; Smyrniotis, P. Z (1953). "Transaldolase: The Formation of Fructose-6-Phosphate from Sedoheptulose-7-Phosphate ... "Structure and Function of Sedoheptulose-7-phosphate Isomerase, a Critical Enzyme for Lipopolysaccharide Biosynthesis and a ...
This enzyme participates in pentose phosphate pathway. It employs one cofactor, FAD. Bak TG (July 1967). "Studies on glucose ...
This enzyme participates in pentose phosphate pathway. Ribokinase (RK) belongs to the phosphofructokinase B (PfkB) family of ... d-ribose 5-phosphate Thus, the two substrates of this enzyme are ATP and d-ribose, whereas its two products are ADP and d- ... ribose 5-phosphate. The systematic name of this enzyme class is ATP:d-ribose 5-phosphotransferase. Other names in common use ... identification of a novel motif implicated in phosphate and magnesium ion binding and substrate inhibition". Biochemistry. 41 ( ...
Palmer AM (1999). "The activity of the pentose phosphate pathway is increased in response to oxidative stress in Alzheimer's ... Palmer AM (1999). "The activity of the pentose phosphate pathway is increased in response to oxidative stress in Alzheimer's ... This enzyme participates in pentose phosphate pathway. It employs one cofactor, manganese. The general structure, as well as ... Dickens F, Glock GE (1951). "Direct oxidation of glucose-6-phosphate, 6-phosphogluconate and pentose-5-phosphates by enzymes of ...
... phosphate-acetylating). This enzyme participates in pentose phosphate pathway. Schramm M, Klybas V, Racker E (1958). " ... adding phosphate; acetyl-phosphate-forming). Other names in common use include D-fructose-6-phosphate D-erythrose-4-phosphate- ... phosphate ⇌ {\displaystyle \rightleftharpoons } acetyl phosphate + D-erythrose 4-phosphate + H2O This enzyme belongs to the ... The enzyme fructose-6-phosphate phosphoketolase (EC 4.1.2.22) catalyzes the chemical reaction D-fructose 6-phosphate + ...
This enzyme participates in pentose phosphate pathway. It employs one cofactor, copper. BEAN RC, HASSID WZ (1956). " ...
This occurs via the pentose phosphate pathway. The NOX2 enzyme is bound in the phagolysosome membrane. Post bacterial ... Implicated pathways include NF-κB, PI3K, HIFs and MAPKs. In humans, mitochondrial ROS is required alongside those released in ... Imlay JA (2003). "Pathways of oxidative damage". Annual Review of Microbiology. 57: 395-418. doi:10.1146/annurev.micro. ... There are 3 main pathways for the generation of reactive oxygen species or reactive nitrogen species (RNS) in effector cells: ...
This enzyme participates in pentose phosphate pathway. It employs one cofactor, FAD. Matsushita K, Shinagawa E, Ameyama M (1982 ...
This enzyme participates in pentose phosphate pathway. As of late 2007, 6 structures have been solved for this class of enzymes ... COHEN SS (1951). "Gluconokinase and the oxidative path of glucose-6-phosphate utilization". J. Biol. Chem. 189 (2): 617-28. ...
This enzyme participates in pentose phosphate pathway. FRAMPTON EW, WOOD WA (1961). "Purification and properties of 2- ...
This enzyme participates in pentose phosphate pathway. It employs one cofactor, FAD. As of late 2007, 8 structures have been ...
This enzyme participates in pentose phosphate pathway. Hove-Jensen B, Rosenkrantz TJ, Haldimann A, Wanner BL (2003). " ... with a phosphate group as acceptor. The systematic name of this enzyme class is ATP:ribose-1,5-bisphosphate phosphotransferase ... dual role in phosphonate degradation and NAD biosynthesis pathways". J. Bacteriol. 185 (9): 2793-801. doi:10.1128/JB.185.9.2793 ...
This enzyme participates in pentose phosphate pathway. It employs one cofactor, PQQ. Ameyama M, Nonobe M, Hayashi M, Shinagawa ...
This enzyme participates in the pentose phosphate pathway. As of late 2007, only one structure has been solved for this class ... Andreesen JR, Gottschalk G (1969). "The occurrence of a modified Entner-doudoroff pathway in Clostridium aceticum". Arch. ...
Pentose phosphate pathway Rosenberg LL, Arnon DI (1955). "The preparation and properties of a new glyceraldehyde-3-phosphate ... Glyceraldehyde-3-phosphate dehydrogenase (NADP+) catalyzes GAP + NADP+ + H2O → 3-PG + NADPH + H+ Glyceraldehyde-3-phosphate ... Glyceraldehyde-3-phosphate dehydrogenase (NADP+) (EC 1.2.1.9) (GAPN) is an enzyme that irreversibly catalyzes the oxidation of ... The most familiar variant of glycolysis uses glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoglycerate kinase to ...
... 4-phosphate is an intermediate in the pentose phosphate pathway and the Calvin cycle. Oxidative bacteria can be made ... Kruger, Nicholas J; von Schaewen, Antje (June 2003). "The oxidative pentose phosphate pathway: structure and organisation". ...
This enzyme participates in the pentose phosphate pathway. It employs one cofactor, pyridoxal phosphate. Imanaga Y (1958). " ... Portal: Biology v t e (EC 4.3.1, Pyridoxal phosphate enzymes, Enzymes of unknown structure, All stub articles, Enzyme stubs). ...
R5P is produced in the pentose phosphate pathway in all organisms. The pentose phosphate pathway (PPP) is a metabolic pathway ... in two different metabolic pathways: the pentose phosphate pathway and glycolysis. The relationship between the two pathways ... Ribose 5-phosphate (R5P) is both a product and an intermediate of the pentose phosphate pathway. The last step of the oxidative ... "Structure of Escherichia coli ribose-5-phosphate isomerase: a ubiquitous enzyme of the pentose phosphate pathway and the Calvin ...
Berg J, Tymoczko J, Stryer L (2012). "The Calvin Cycle and the Pentose Phosphate Pathway". Biochemistry (7th ed.). New York: W. ... pyruvate-phosphate dikinase, pyruvate-phosphate ligase, pyruvic-phosphate dikinase, pyruvic-phosphate ligase, pyruvate, Pi ... Reeves RE, Menzies RA, Hsu DS (October 1968). "The pyruvate-phosphate dikinase reaction. The fate of phosphate and the ... Pyruvate, phosphate dikinase, or PPDK (EC 2.7.9.1) is an enzyme in the family of transferases that catalyzes the chemical ...
Once formed, galactonate may enter the pentose phosphate pathway. Thus, oxidation to galactonate serves as an alternate pathway ... The first reaction of this pathway is the reduction of aldoses, types of sugars including galactose, to sugar alcohols. Recent ... This oxidative pathway renders accumulated galactonate less harmful than accumulated galactitol.[citation needed] In many ... Galactose is converted into glucose by the action of three enzymes, known as the Leloir pathway. There are diseases associated ...
The pentose phosphate pathway is an alternative method of oxidizing glucose. It occurs in the liver, adipose tissue, adrenal ... ISBN 978-1-337-51421-7. Ramos-Martinez, Juan Ignacio (2017-01-15). "The regulation of the pentose phosphate pathway: Remember ... This molecule can then be converted to glucose-6-phosphate, an intermediate in the glycolysis pathway. Glucose-6-phosphate can ... For example, the pathway leading from pyruvate to glucose-6-phosphate requires 4 molecules of ATP and 2 molecules of GTP to ...
A network of reactions adopted from the glycolysis pathway and the pentose phosphate pathway is shown in which the labeled ... Kruger, Nicholas; Antje von Schaewen (2003). "The oxidative pentose phosphate pathway: structure and organisation" (PDF). ... The 2,3-13C T3P can now be reacted with sedoheptulose 7-phosphate (S7P) to form an unlabeled erythrose 4-phosphate(E4P) and a 5 ... As shown, if the metabolite only takes the pathway down the left side, it remains in a 50-50 ratio of uniformly labeled to ...
... and the Pentose Phosphate Pathway". Lehninger Principles of Biochemistry (5 ed.). W H Freeman & Co. pp. 527-568. ISBN 978- ... The Embden-Meyerhoff Pathway (EMP))", Textbook of Veterinary Physiological Chemistry (Third Edition), Boston: Academic Press, ...
Ribulose and xylulose occur in the pentose phosphate pathway. Galactose, a component of milk sugar lactose, is found in ... A 2 ATP investment is required in the early steps of glycolysis to phosphorylate Glucose to Glucose 6-Phosphate (G6P) and ... Monosaccharides with three carbon atoms are called trioses, those with four are called tetroses, five are called pentoses, six ... There are two major metabolic pathways of monosaccharide catabolism: glycolysis and the citric acid cycle. In glycolysis, oligo ...
Not only ribose 5-phosphate but also fructose 6-phosphate are an intermediate of the pentose-phosphate pathway which generates ... Not only ribose 5-phosphate but also fructose 6-phosphate are an intermediate of the pentose-phosphate pathway which generates ... and pentoses from glucose polymers and their degradation products.) oxidative pentose phosphate pathways, gluconeogenesis, ... "Sugar-phosphate backbone". 12 September 2020. "Phosphate Backbone". "Case Study: Sugar Phosphates - Methods for Analysis of ...
Antonenkov, Vasily D. (Jul 1989). "Dehydrogenases of the pentose phosphate pathway in rat liver peroxisomes". European Journal ... in the pentose phosphate pathway, which is important for energy metabolism. It is vigorously debated whether peroxisomes are ... and the NADP-dehydrogenases of the pentose-phosphate pathway. It has been demonstrated that peroxisomes generate superoxide (O2 ... The specific metabolic pathways that occur exclusively in mammalian peroxisomes are: α-oxidation of phytanic acid β-oxidation ...
The chemical logic behind the pentose phosphate pathway Pentose+Phosphate+Pathway at the U.S. National Library of Medicine ... The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt and the HMP Shunt) ... 3 ribulose-5-phosphate → 1 ribose-5-phosphate + 2 xylulose-5-phosphate → 2 fructose-6-phosphate + glyceraldehyde-3-phosphate ... the pentose phosphate pathway appears to have a very ancient evolutionary origin. The reactions of this pathway are mostly ...
A positive feedback between cholesterol synthesis and the pentose phosphate pathway (PPP) rather than glycolysis was formed in ... Unexpectedly, HMGCR (3-hydroxy-3-methylglutaryl-CoA reductase) and G6PD (glucose-6-phosphate dehydrogenase), the rate-limiting ... The pentose phosphate pathway (PPP) is a metabolic pathway parallel to glycolysis [15]. It is widely accepted that glycolysis ... Hu, J., Liu, N., Song, D. et al. A positive feedback between cholesterol synthesis and the pentose phosphate pathway rather ...
... pentose phosphate pathway) flux. However, it remains unexplored if TIGAR plays an important role in DNA damage and repair. This ... The Cdk5-AMT signal pathway involved in regulation of DDR by TIGAR defines a new role of TIGAR in cancer cell survival and it ... Cosentino, C., Grieco, D. and Costanzo, V. ATM activates the pentose phosphate pathway promoting anti-oxidant defence and DNA ... Yu, HP., Xie, JM., Li, B. et al. TIGAR regulates DNA damage and repair through pentosephosphate pathway and Cdk5-ATM pathway. ...
Functional significance of the pentose phosphate pathway and glutathione reductase in the anti-oxidant defences of human sperm. ... Functional significance of the pentose phosphate pathway and glutathione reductase in the anti-oxidant defences of human sperm ... Functional significance of the pentose phosphate pathway and glutathione reductase in the anti-oxidant defences of human sperm ... Williams, AC & Ford, WCL 2004, Functional significance of the pentose phosphate pathway and glutathione reductase in the anti- ...
The pentose phosphate pathway was blocked either by disruption of the GND1 gene, one of the isogenes of 6-phosphogluconate ... The pentose phosphate pathway was blocked either by disruption of the GND1 gene, one of the isogenes of 6-phosphogluconate ... The pentose phosphate pathway was blocked either by disruption of the GND1 gene, one of the isogenes of 6-phosphogluconate ... The pentose phosphate pathway was blocked either by disruption of the GND1 gene, one of the isogenes of 6-phosphogluconate ...
️ In pentose phosphate pathway, which of the following process is lacking? ... In the pentose phosphate pathway, glucose 6-phosphate is directly oxidized without entering glycolysis. Even Krebs cycle and ... The pentose phosphate pathway also called the hexose monophosphate shunt, is a shunt from glycolysis designed to produce either ... oxidative phosphorylation doesnt happen in pentose phosphate pathway.. So, the correct answer is All of the above.. ...
Glucose-6-phosphate dehydrogenase,br/,Heartwood formation,br/,Oxidative pentose phosphate pathway,br/,Phenolic heartwood ... Oxidative pentose phosphate pathway and pyridine nucleotides in relation to heartwood formation in Robinia pseudoacacia L. ... Glucose-6-phosphate-dehydrogenase,br/,Elicitor,br/,Tissues,br/,Potato,br/,Dinucleotides,br/,Protoplasts,br/,Metabolism,br/, ... In the present paper we report on the key position of the oxidative pentose phosphate pathway (OPP) for this process. The OPP ...
The pentose phosphate pathway is also called as the phosphogluconate pathway or hexose monophosphate shunt. ... Pentose Phosphate Pathway. June 5, 2023. by Sagar Aryal The pentose phosphate pathway is a metabolic pathway parallel to ... Regulation of Pentose Phosphate Pathway. *Key enzyme in the pentose-phosphate pathway is glucose-6-phosphate dehydrogenase. ... Purpose of Pentose Phosphate Pathway. *Pentose phosphate pathway functions as an alternative route for glucose oxidation that ...
Powered by cMonkey algorithm developed in Baliga lab at Institute for Systems Biology ...
This project is supported by the University of Maryland, School of Pharmacy, Mass Spectrometry Center, a Waters Center of Excellence. The center is an NIH-investigator funded research and core facility that supports a wide range of cutting-edge metabolomic studies. The Center is supported through a center grant from the University of Maryland and NIH grants to its members. The PAMDB project is affiliated with The Metabolomics Innovation Centre (TMIC) a leading metabolomics research and service center funded through Genome Alberta, Genome British Columbia and Genome Canada ...
Mechanism and importance of Pentose Phosphate Pathway with reactions. ... Pentose Phosphate Pathway Steps Pentose Phosphate Pathway. There are two-phase of Pentose Phosphate Pathway such as oxidative ... Purpose of Pentose Phosphate Pathway - What is the purpose of the pentose phosphate pathway? The Pentose Phosphate Pathway (PPP ... Location of Pentose Phosphate Pathway - Where does pentose phosphate pathway occur? The Pentose Phosphate Pathway (PPP) ...
The Pentose Phosphate Pathway PDF Book aims to explore the pentose phosphate cycle and the practical techniques applied in its ... The text is recommended for biologists and biochemists who would like to understand further the pentose phosphate pathway and ... D-Erythrose 4-Phosphate as an Intermediate of the Pathway. The Transketolase-Transaldolase Coupled Reaction and the Existence ... The main focus of the book is the pentose phosphate cycle in animals as well as microorganisms, and does not discuss the one ...
molecule of glucose through the pentose phosphate pathway?. 9. Which two (2) molecules are produced during the pentose ... Gluconeogenesis, Glycogen, and the Pentose Phosphate Pathway February 22, 2023. /in Uncategorized /by Paul. .awasam-promo { ... pentose phosphate pathway and their roles in glucose metabolism. Based on the topics ... 7. What are the main products of the pentose phosphate pathway, and how does ...
... is divided into an oxidative branch that makes pentose phosphates and a non-oxidative branch that consumes pentose phosphates, ... The reaction sequence in the Calvin-Benson cycle is from triose phosphates to pentose phosphates, the opposite of the typical ... consuming three ATP per glucose 6-phosphate consumed. A constitutive operation of this shunt occurs in the cytosol and gives ... releasing reactions when the oxidative pentose phosphate pathway bypasses the anabolic pentose phosphate pathway of the Calvin- ...
Quantification of sugar phosphate intermediates of the pentose phosphate pathway by LC-MS/MS: application to two new inherited ... The pentose phosphate pathway (PPP) is a central pathway of the cellular carbohydrate metabolism. The PPP is directly ... ribose 5-phosphate (r5p), erythrose 4-phosphate (e4p), xylulose 5-phosphate or ribulose 5-phosphate (x5p), glucose 6-phosphate ... ribose 5-phosphate (r5p), erythrose 4-phosphate (e4p), xylulose 5-phosphate or ribulose 5-phosphate (x5p), glucose 6-phosphate ...
Resonance SpectroscopyMetabolic Networks and PathwaysMetabolomicsOceans and SeasPentose Phosphate PathwaySugar PhosphatesRalser ... However, key biochemical reactions of glycolysis and the pentose phosphate pathway (PPP), ancient metabolic pathways central to ... Conditional iron and pH-dependent activity of a non-enzymatic glycolysis and pentose phosphate pathway. ... has binding affinity toward metabolic sugar phosphates and drives metabolism-like reactivity acting as both catalyst and ...
title = "Assessing the pentose phosphate pathway using [2, 3-13C2]glucose",. abstract = "The pentose phosphate pathway (PPP) is ... Assessing the pentose phosphate pathway using [2, 3-13C2]glucose. / Lee, Min Hee; Malloy, Craig R.; Corbin, Ian R. et al. In: ... Lee, M. H., Malloy, C. R., Corbin, I. R., Li, J., & Jin, E. S. (2019). Assessing the pentose phosphate pathway using [2, 3-13C2 ... Lee, MH, Malloy, CR, Corbin, IR, Li, J & Jin, ES 2019, Assessing the pentose phosphate pathway using [2, 3-13C2]glucose, NMR ...
Carbohydrates: gluconeogenesis, pentose phosphate pathway. *Electron transport, oxidative phosphorylation. *Mitochondrial ... The enzymes and intermediates of major catabolic and anabolic pathways. Their regulation and integration in health and disease ...
Pentose Phosphate Pathway;. Bioactive Lipids & Lipid Receptors;. Omega-3 & -6 Fatty Acid Functions;. The Endocannabinoids;. The ...
Pathways affected by treatments were related to amino acid and nucleic acid metabolism in both rumen fluid and serum (p , 0.05 ... Pentose phosphate pathway. 0.003. 0.07. 0.001. Amino sugar and nucleotide sugar metabolism. 0.004. 0.109. 0.001. ... Twenty metabolic pathways were affected by seed type, but only two pathways were affected by isoflavones (p , 0.05). ... Finally, pathway analyses were performed to determine metabolic pathways that were significantly impacted in rumen fluid and ...
Glucose is then redirected into the pentose phosphate pathway (PPP) to produce NADH and nucleotides instigating an increase in ... J. Boada, T. Roig, X. Perez et al., "Cells overexpressing fructose-2,6-bisphosphatase showed enhanced pentose phosphate pathway ... It will then be either metabolized through glycolysis or diverted to the pentose phosphate pathway (PPP). Glucose-derived ... pathway or the extrinsic (death receptor) pathway. The central players in both pathways are the family of caspases (Figure 2). ...
PENTOSE-PHOSPHATE PATHWAY; PREVENTION OF TUBERCULOSIS; PULMONARY TUBERCULOSIS; RESISTANT TUBERCULOSIS; RESPIRATORY INFECTION; ...
The glucose-6-phosphate dehydrogenase activity was decreased and the transketolase activity was unaltered in intercostal muscle ... Kukhta V.K. (1976) Activity of enzymes of pentosephosphate pathway in the erythrocytes, myocardium and intercostal muscle of ... Activity of enzymes of pentosephosphate pathway in the erythrocytes, myocardium and intercostal muscle of patients with mitral ... Activity of enzymes of pentosephosphate pathway in the erythrocytes, myocardium and intercostal muscle of patients with mitral ...
Pathway. rn00010 Glycolysis / Gluconeogenesis. rn00030 Pentose phosphate pathway. rn00260 Glycine, serine and threonine ... Pathway (15) KEGG PATHWAY (15) Chemical reaction (32) KEGG ENZYME (14) KEGG REACTION (18) Gene (10) KEGG ORTHOLOGY (10) All ... Ontology (1) KEGG BRITE (1) Pathway (19) KEGG PATHWAY (18) KEGG MODULE (1) Chemical substance (4) KEGG COMPOUND (4) Chemical ... adenosylcobinamide kinase / adenosylcobinamide-phosphate guanylyltransferase [EC:2.7.1.156 2.7.7.62]. K05979 2- ...
... pentose-phosphate pathway, gluconeogenesis and photosynthesis. Practical training in study and analysis of metabolic pathways ...
The Pentose Phosphate Pathway Regulates the Circadian Clock. (2016). Cell Metabolsim. Rey, G., Valekunja, U.K., Feeney, K.A., ... Machine Learning and Pathway Analysis-Based Discovery of Metabolomic Markers Relating to Chronic Pain Phenotypes. Miettinen T, ... Role of the cystathionine β-synthase / H2S pathway in the development of cellular metabolic dysfunction and pseudohypoxia in ...
The Pentose Phosphate Pathway in Cancer: Regulation and Therapeutic Opportunities. Ghanem N, El-Baba C, Araji K, El-Khoury R, ...
Pentose Phosphate Pathway. Glycogen. Galactose and Lactose. N-Acetyl Sugars and Hyaluronan. Alcohol and Aldehyde Dehydrogenases ... p53 Pathway. RB1 and Related Functions. E2F Pathways. Anaphase-promoting Complex. Spindle, M phase, and Meiosis. Additional ... Hedgehog and Related Pathways. Notch Pathway. Wnt Signals. Planar Cell Polarity (includes Bardet�Biedl syndrome loci and cilia ... NF-κB Pathway. mTOR Pathway. Nucleotide and Nucleoside Receptors. Signalosome. Integrins (includes tetraspanins). Netrins and ...
... pentose-phosphate pathway, gluconeogenesis and photosynthesis. Practical training in study and analysis of metabolic pathways ... regulation of catabolic pathways, chemotaxis. Nitrogen metabolism, iron-scavenging. Alternative electron acceptors: ...
  • It generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-phosphate, a precursor for the synthesis of nucleotides. (wikipedia.org)
  • Production of ribose 5-phosphate (R5P), used in the synthesis of nucleotides and nucleic acids. (wikipedia.org)
  • The entire set of reactions can be summarized as follows: The overall reaction for this process is: Glucose 6-phosphate + 2 NADP+ + H2O → ribulose 5-phosphate + 2 NADPH + 2 H+ + CO2 Net reaction: 3 ribulose-5-phosphate → 1 ribose-5-phosphate + 2 xylulose-5-phosphate → 2 fructose-6-phosphate + glyceraldehyde-3-phosphate Glucose-6-phosphate dehydrogenase is the rate-controlling enzyme of this pathway[citation needed]. (wikipedia.org)
  • The phosphopentose pathway (PPP), which converts glucose-6-phosphate to ribose-5-phosphate for synthesis of nucleotides and NADPH to reduce DNA damage caused by ROS was reported to be activated in DDR 2 . (nature.com)
  • The pentose phosphate pathway is a metabolic pathway parallel to glycolysis which generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-phosphate. (microbenotes.com)
  • Ribulose-5-phosphate is isomerized to ribose-5-phosphate or epimerized to xylulose-5-phosphate. (microbenotes.com)
  • Ribose-5-phosphate and xylulose-5-phosphate undergo reactions, catalyzed by transketolase and transaldolase, that transfer carbon units, ultimately forming fructose 6-phosphate and glyceraldehyde-3-phosphate. (microbenotes.com)
  • When NADPH levels are low, the oxidative reactions of the pathway can be used to generate ribose-5-phosphate for nucleotide biosynthesis. (microbenotes.com)
  • When NADPH levels are high, the reversible nonoxidative portion of the pathway can be used to generate ribose-5-phosphate for nucleotide biosynthesis from fructose-6-phosphate and glyceraldehyde-3-phosphate. (microbenotes.com)
  • In scientific terms, the PPP is an essential metabolic pathway that functions concurrently with glycolysis , presenting itself as a quintessential player in maintaining cellular homeostasis through its diligent role in generating NADPH, pentoses, and ribose 5-phosphate. (microbiologynote.com)
  • The Pentose Phosphate Pathway (PPP) is a metabolic pathway parallel to glycolysis that produces NADPH, pentoses (5-carbon sugars), and ribose 5-phosphate, a precursor for nucleotide synthesis. (microbiologynote.com)
  • Dihydroxacetone phosphate (dhap), ribose 5-phosphate (r5p), erythrose 4-phosphate (e4p), xylulose 5-phosphate or ribulose 5-phosphate (x5p), glucose 6-phosphate or fructose-6-phosphate (g6p), sedoheptulose 7-phosphate (s7p) and 6-phosphogluconate (6pg) to generate calibration curves for an accurate quantification. (researchsquare.com)
  • Key enzyme in the pentose-phosphate pathway is glucose-6-phosphate dehydrogenase. (microbenotes.com)
  • A genetic aberration in glucose 6-phosphate dehydrogenase, a pivotal enzyme in the PPP, can disrupt this biochemical harmony, underscoring the pathway's indispensability in cellular metabolism and defense mechanisms. (microbiologynote.com)
  • It can be generated from D-glyceraldehdye-3 phosphate via the enzyme 2-Deoxyribose 5-phosphate aldolase (DERA). (hmdb.ca)
  • Deoxyribose 5-phosphate can also be generated from 2-Deoxy-D-ribose via the enzyme Ribokinase (EC 2.7.1.15). (hmdb.ca)
  • g6pd is the enzyme for what two pathways? (studystack.com)
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency and pyruvate kinase (PK) deficiency are the 2 most common enzyme defects that cause hemolytic anemia. (medscape.com)
  • EC 3.1.3.48 ) catalyse the removal of a phosphate group attached to a tyrosine residue, using a cysteinyl-phosphate enzyme intermediate. (embl.de)
  • Wernicke-Korsakoff syndrome Symptoms and Signs is caused by a partial deficiency of transketolase, which is an enzyme for the pentose phosphate pathway that requires thiamin as a cofactor. (merckmanuals.com)
  • GSD type Ib is a similar condition that has active G6Pase enzyme activity but with a defect in the glucose-6-phosphate transporter protein. (medscape.com)
  • Embarking on an exploration into cellular metabolism, the Pentose Phosphate Pathway (PPP) commands particular attention, not merely for its role in glucose metabolism but also for its crucial involvement in cellular biosynthesis and antioxidant defenses. (microbiologynote.com)
  • pentose phosphate pathway and their roles in glucose metabolism. (expert-tutor.net)
  • The pentose phosphate pathway (PPP) is a central pathway of the cellular carbohydrate metabolism. (researchsquare.com)
  • Fe(II), the dominant transition metal component of Archean oceanic sediments, has binding affinity toward metabolic sugar phosphates and drives metabolism-like reactivity acting as both catalyst and cosubstrate. (figshare.com)
  • In addition to its role in glucose metabolism, this pathway also regulates the redirection of free amino acids to protein synthesis via the mTOR-signaling pathway. (hindawi.com)
  • B[a]P caused enhanced metabolism of each dye assessed despite reductions in mitochondrial membrane potential and was reversed by 6-aminonicotinamide (6AN)-a glucose-6-phosphate dehydrogenase inhibitor. (cdc.gov)
  • The primary results of the pathway are: The generation of reducing equivalents, in the form of NADPH, used in reductive biosynthesis reactions within cells (e.g. fatty acid synthesis). (wikipedia.org)
  • Erythrocytes, for example, generate a large amount of NADPH through the pentose phosphate pathway to use in the reduction of glutathione. (wikipedia.org)
  • In this phase, two molecules of NADP+ are reduced to NADPH, utilizing the energy from the conversion of glucose-6-phosphate into ribulose 5-phosphate. (wikipedia.org)
  • An NADPH-utilizing pathway forms NADP+, which stimulates Glucose-6-phosphate dehydrogenase to produce more NADPH. (wikipedia.org)
  • In this study we increased the ethanol yield and decreased the xylitol yield by lowering the flux through the NADPH-producing pentose phosphate pathway. (lu.se)
  • Metabolic flux modeling of TMB3255 confirmed that the NADPH-producing pentose phosphate pathway was blocked and that xylose reduction was mediated only by NADH, leading to a lower rate of xylose consumption. (lu.se)
  • The pentose phosphate pathway also called the hexose monophosphate shunt, is a shunt from glycolysis designed to produce either NADPH or ribose or both. (toppr.com)
  • The OPP plays a crucial role in anabolic processes and is involved in the interconversion and rearrangements of sugar-phosphates with the net production of NADPH. (mpg.de)
  • Glucose-6-phosphate dehydrogenase is stimulated by NADP+ and inhibited by NADPH and by palmitoyl-CoA (part of the fatty acid synthesis pathway). (microbenotes.com)
  • The pentose phosphate pathway produces NADPH for fatty acid synthesis. (microbenotes.com)
  • The PPP showcases its role by executing two meticulously orchestrated phases: the oxidative phase, where glucose 6-phosphate is oxidized to produce NADPH and ribulose 5-phosphate, and the non-oxidative phase, which is engaged in the synthesis of 5-carbon sugars, contributing significantly to the synthesis of nucleotides and nucleic acids. (microbiologynote.com)
  • Conversely, in tissues where the biosynthetic activities, particularly those related to fatty acid and sterol synthesis, are in full swing, the NADPH produced by the PPP is channeled to support these reductive biosynthetic pathways. (microbiologynote.com)
  • Produces pentose sugars for nucleic acid synthesis and main producer of NADPH reducing power. (lu.se)
  • D-glucose 6-phosphate + NADPH(+) = d-glucono-1,5-lactone 6-phosphate + NADPH. (lu.se)
  • fructose-6- phosphate) for nucleotide synthesis and glycolysis. (microbenotes.com)
  • Under these conditions, the fructose-6-phosphate and glyceraldehyde-3-phosphate generated in the pathway reenter glycolysis. (microbenotes.com)
  • Unexpectedly, HMGCR (3-hydroxy-3-methylglutaryl-CoA reductase) and G6PD (glucose-6-phosphate dehydrogenase), the rate-limiting enzymes of cholesterol synthesis and the PPP, were identified as direct targets of microRNA-206. (nature.com)
  • The enzymes and intermediates of major catabolic and anabolic pathways. (sfu.ca)
  • Other deficiencies include those of glycolytic enzymes or enzymes in the pentose phosphate pathway. (merckmanuals.com)
  • With GSDs, carbohydrate metabolic pathways are blocked at various levels and excess glycogen accumulates in affected tissues. (medscape.com)
  • Alternately Deoxyribose 5-phosphate can be converted to D-glyceraldehyde-3 phosphate that can then feed into the pentose phosphate pathway. (hmdb.ca)
  • In tissues of Robinia pseudoacacia L. which are transferred to heartwood, enhanced activities of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PCDH) are present. (mpg.de)
  • Decrease in activities of glucose-6-phosphate dehydrogenase and transketolase was observed in erythrocytes of patients with mitral stenosis. (msk.ru)
  • G6PD deficiency - A hereditary disease that disrupts the pentose phosphate pathway RNA Thiamine deficiency Frank Dickens FRS Alfarouk, Khalid O. (wikipedia.org)
  • citation needed] Dietary pentose sugars derived from the digestion of nucleic acids may be metabolized through the pentose phosphate pathway, and the carbon skeletons of dietary carbohydrates may be converted into glycolytic/gluconeogenic intermediates. (wikipedia.org)
  • Concurrently, the PPP can transmute the carbon skeletons of dietary carbohydrates into intermediates apt for glycolytic and gluconeogenic pathways, thereby enabling the cell to adeptly navigate through the metabolic intricacies and adapt to varying physiological contexts. (microbiologynote.com)
  • G6PD deficiency affects the pentose phosphate pathway, and PK deficiency affects the glycolytic pathway. (medscape.com)
  • Glycolytic Pathway Defects Glycolytic pathway defects are autosomal recessive red blood cell metabolic disorders that cause hemolytic anemia. (merckmanuals.com)
  • The glycolytic pathway is one of the. (merckmanuals.com)
  • [ 3 ] Increased use of the glycolytic pathway also increases lipogenesis, leading to hypercholesterolemia and hypertriglyceridemia , which can result in hepatic steatosis and pancreatitis. (medscape.com)
  • Levels of glucose-6-phosphate dehydrogenase are increased in the liver and adipose tissue when large amounts of carbohydrates are consumed. (microbenotes.com)
  • The diagram below illustrates metabolic pathways of carbohydrates. (medscape.com)
  • G6Pase hydrolyzes glucose-6-phosphate (G6P), an end-product of both glycogenolysis and gluconeogenesis, into glucose before it can be released into circulation. (medscape.com)
  • It is an important pathway that generates precursors for nucleotide synthesis andis especially important in red blood cells (erythrocytes). (microbenotes.com)
  • Dietary pentose sugars, a derivative of nucleic acid digestion, can be intertwined with the PPP, thereby revealing another layer of metabolic flexibility and adaptability provided by this pathway. (microbiologynote.com)
  • Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked enzymatic defect common in people with African ancestry that can result in hemolysis after acute illnesses or intake of oxidant. (merckmanuals.com)
  • The glucose-6-phosphate dehydrogenase activity was decreased and the transketolase activity was unaltered in intercostal muscle of the patients. (msk.ru)
  • Oxidative pentose phosphate pathway and pyridine nucleotides in relation to heartwood formation in Robinia pseudoacacia L. (mpg.de)
  • Lipids, amino acids, and nucleotides necessary for the biosynthesis of the daughter cells are mostly provided by intermediate metabolites of these pathways. (hindawi.com)
  • The Cdk5-AMT signal pathway involved in regulation of DDR by TIGAR defines a new role of TIGAR in cancer cell survival and it suggests that TIGAR may be a therapeutic target for cancers. (nature.com)
  • The pentose phosphate pathway (PPP) is essential for reductive biosynthesis, antioxidant processes and nucleotide production. (elsevierpure.com)
  • Production of erythrose 4-phosphate (E4P) used in the synthesis of aromatic amino acids. (wikipedia.org)
  • It has been shown in a number of organisms that deoxynucleosides or deoxyriboses cause the induction of aldolases (such as DERA) involved in their catabolism, leading to the utilisation of the pentose moiety as carbon and energy source. (hmdb.ca)
  • Williams, AC & Ford, WCL 2004, ' Functional significance of the pentose phosphate pathway and glutathione reductase in the anti-oxidant defences of human sperm ', Biology of Reproduction , vol. 71, pp. 1309 - 1316. (bris.ac.uk)
  • Aromatic amino acids, in turn, are precursors for many biosynthetic pathways, including the lignin in wood. (wikipedia.org)
  • The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt and the HMP Shunt) is a metabolic pathway parallel to glycolysis. (wikipedia.org)
  • The pentose phosphate pathway is also called as the phosphogluconate pathway or hexose monophosphate shunt. (microbenotes.com)
  • The remaining carbons form ribulose-5-phosphate. (microbenotes.com)
  • Ribulose bisphosphate carboxylase (Rubisco) plays an important role in the Calvin reductive pentose phosphate pathway. (nih.gov)
  • Decreasing the phosphoglucose isomerase activity by 90% also lowered the pentose phosphate pathway flux. (lu.se)
  • Western blot was carried out to detect the expression levels of autophagic-related proteins (Unc-51 like autophagy activating kinase 1, beclin 1, autophagy related 5, microtubule-associated protein 1A/1B-light chain 3, ubiquitin-binding protein p62), glycolysis-related proteins (hexokinase 2, phosphofructokinase, pyruvate kinase M2) and activated protein kinase signalling pathway proteins. (ijpsonline.com)
  • The reaction sequence in the Calvin-Benson cycle is from triose phosphates to pentose phosphates, the opposite of the typical direction of the non-oxidative PPP. (mdpi.com)
  • The Entner-Doudoroff and nonoxidative pentose phosphate pathways bypass glycolysis and the oxidative pentose phosphate pathway in Ralstonia solanacearum. (ufz.de)
  • Accumulation of G6P substrate leads to increased utilization of the glycolysis pathway for energy production, resulting in lactic acidosis. (medscape.com)
  • The reactions of the pathway were elucidated in the early 1950s by Bernard Horecker and co-workers. (wikipedia.org)
  • Organic waste conversion through anaerobic digestion: A critical insight into the metabolic pathways and microbial interactions. (ufz.de)
  • Reduced oxidative pentose phosphate pathway flux in recombinant xylose-utilizing Saccharomyces cerevisiae strains improves the ethanol yield from xylose. (lu.se)
  • Please note that proteins can be included in multiple pathways, ie. (embl.de)
  • Autophagy is a process that relies on lysosomal pathways for the degradation of cytoplasmic proteins and organelles and plays an important role in the pathology of brain injury such as hypoxia ischemia[ 3 ]. (ijpsonline.com)
  • Efficient System Wide Metabolic Pathway Comparisons in Multiple Microbes Using Genome to KEGG Orthology (G2KO) Pipeline Tool. (ufz.de)
  • Several deficiencies in the level of activity (not function) of glucose-6-phosphate dehydrogenase have been observed to be associated with resistance to the malarial parasite Plasmodium falciparum among individuals of Mediterranean and African descent. (wikipedia.org)
  • While the pentose phosphate pathway does involve oxidation of glucose, its primary role is anabolic rather than catabolic. (wikipedia.org)
  • Pentose phosphate pathway functions as an alternative route for glucose oxidation that does not directly consume or produce ATP. (microbenotes.com)
  • Acetyl-CoA generated by the beta-oxidation pathway enters the mitochondrial TCA cycle, where it is further oxidized to generate NADH and FADH 2 . (assignmentexpert.com)
  • The pathway is especially important in red blood cells (erythrocytes). (wikipedia.org)
  • Navigating through the biochemical intricacies of the PPP provides a splendid panorama of how cells masterfully exploit metabolic pathways, in a manner that is attuned to their physiological, biosynthetic, and defensive needs, thereby maintaining a harmonious cellular and systemic physiological state. (microbiologynote.com)
  • The Pentose Phosphate Pathway (PPP) primarily resides within the cytosol of cells, which is the aqueous component of the cytoplasm, a matrix in which various cellular organelles are suspended and numerous metabolic reactions transpire. (microbiologynote.com)
  • Autophagy-dependent metabolic reprograming leads to pentose phosphate pathway addiction in cells with hyperactive mTORC1. (mdanderson.org)
  • Deoxyribose 5-phosphate is a a metabolite in the pentose phosphate pathway. (hmdb.ca)
  • The pentose phosphate pathway (PPP) is divided into an oxidative branch that makes pentose phosphates and a non-oxidative branch that consumes pentose phosphates, though the non-oxidative branch is considered reversible. (mdpi.com)