Kinetics: The rate dynamics in chemical or physical systems.Enzymes: Biological molecules that possess catalytic activity. They may occur naturally or be synthetically created. Enzymes are usually proteins, however CATALYTIC RNA and CATALYTIC DNA molecules have also been identified.Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Enzyme Assays: Methods used to measure the relative activity of a specific enzyme or its concentration in solution. Typically an enzyme substrate is added to a buffer solution containing enzyme and the rate of conversion of substrate to product is measured under controlled conditions. Many classical enzymatic assay methods involve the use of synthetic colorimetric substrates and measuring the reaction rates using a spectrophotometer.Microsomes, Liver: Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Models, Biological: 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.Glucuronides: Glycosides of GLUCURONIC ACID formed by the reaction of URIDINE DIPHOSPHATE GLUCURONIC ACID with certain endogenous and exogenous substances. Their formation is important for the detoxification of drugs, steroid excretion and BILIRUBIN metabolism to a more water-soluble compound that can be eliminated in the URINE and BILE.Biocatalysis: The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.Dealkylation: The removing of alkyl groups from a compound. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Glucuronosyltransferase: A family of enzymes accepting a wide range of substrates, including phenols, alcohols, amines, and fatty acids. They function as drug-metabolizing enzymes that catalyze the conjugation of UDPglucuronic acid to a variety of endogenous and exogenous compounds. EC 2.4.1.17.ComputersCatalytic Domain: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Hydroxylation: Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)Cytochrome P-450 Enzyme System: A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Quinidine: An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Biotransformation: The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.Molecular Sequence Data: 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.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Escherichia coli: 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.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Amino Acid Sequence: 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.Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.Enzyme Inhibitors: Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.Allosteric Regulation: The modification of the reactivity of ENZYMES by the binding of effectors to sites (ALLOSTERIC SITES) on the enzymes other than the substrate BINDING SITES.Glucokinase: 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.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Microsomes: Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Models, Theoretical: Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Mutation: 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.Thermodynamics: A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)Aryl Hydrocarbon Hydroxylases: A large group of cytochrome P-450 (heme-thiolate) monooxygenases that complex with NAD(P)H-FLAVIN OXIDOREDUCTASE in numerous mixed-function oxidations of aromatic compounds. They catalyze hydroxylation of a broad spectrum of substrates and are important in the metabolism of steroids, drugs, and toxins such as PHENOBARBITAL, carcinogens, and insecticides.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Amino Acid Substitution: The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Oxidation-Reduction: 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).Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Adenosine Triphosphate: 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.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Magnetic Resonance Spectroscopy: 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).Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Bacterial Proteins: Proteins found in any species of bacterium.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Photolysis: Chemical bond cleavage reactions resulting from absorption of radiant energy.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Half-Life: The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Biophysics: The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Ion Channel Gating: The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Biophysical Phenomena: The physical characteristics and processes of biological systems.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Metabolic Clearance Rate: Volume of biological fluid completely cleared of drug metabolites as measured in unit time. Elimination occurs as a result of metabolic processes in the kidney, liver, saliva, sweat, intestine, heart, brain, or other site.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Diffusion: The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
  • An understanding of enzyme mechanisms informs the work but is no longer its main focus. (acs.org)
  • The move toward enzyme-function studies was a theme at the 20th Enzyme Mechanisms Conference held last month in St. Pete Beach, Fla. (acs.org)
  • At the enzyme mechanisms conference last month, Allen, Gerlt, Armstrong, and several other enzymologists described how their research programs are expanding into functional genomics. (acs.org)
  • Gerlt, for example, tries to assign functions to enzymes in families whose members have similar structures and mechanisms. (acs.org)
  • Although these mechanisms are often a complex series of steps, there is typically one "rate-determining step" that determines the overall kinetics. (academic.ru)
  • The biochemical mechanisms involving oxidative stress to explain the relationship between exercise and healthy aging are still unclear. (humankinetics.com)
  • A study of the mechanisms of inheritance involving Mendelian and molecular principles and of genetic change during evolution involving population genetic principles. (conncoll.edu)
  • A comprehensive study of the molecular mechanisms of basic cellular functions involved in human health and disease. (conncoll.edu)
  • She is currently interested in the gene regulatory mechanisms that are involved in specifying particular cell types of the sensory organs in Drosophila. (conncoll.edu)
  • In a relatively few years, it had answered most of the important questions regarding reaction mechanisms and, by the sixties, was involved in heated arguments about classical versus non-classical carbocations â€" a question that could not be answered with the experimental techniques available at the time. (scalacs.org)
  • 1. The human liver UDP-glucuronosyltransferase (UGT) isoforms involved in the glucuronidation of 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of irinotecan (CPT-11), have been studied using microsomes from human liver and insect cells expressing human UGTs (1A1, 1A3, 1A4, 1A6, 1A9, 2B7, 2B15). (nih.gov)
  • Increasing evidence supports that autophagy is involved in the pathophysiological process of APAP-induced liver injury. (deepdyve.com)
  • The recombinant enzyme shows a good thermostability (melting temperature of 63-65 °C), is stable at pH 6-7, and maintains a large part of the starting activity following incubation for 24 h at 25-37 °C. Rh_DypB activity is not affected by 1 M NaCl, 10% DMSO, and 5% Tween-80, i.e., compounds used for dye decolorization or lignin-solubilization processes. (springer.com)
  • 12a,15,16 Use of 'on-off' type probes in enzyme monitoring have potential problems with calibration, as competitive quenching processes can also give rise to the observed emission response. (rsc.org)
  • This problern is espe- cially pressing in connection with research on allosteric enzymes, which are responsible for feedback in metabolic processes. (springer.com)
  • In this paper, we present a method by rigorous mathematics to analyze the general enzyme kinetics model, which is concerned with a single substrate catalyzed by enzyme and transformed into a single product, and it is based on computer algebra technique and the qualitative theory of dynamical system. (hanspub.org)
  • GSTs belong to a family of enzymes that catalyze the conjugation of GSH to a wide variety of chemical toxins ( 4 ) and reactive electrophiles ( 5 ). (aacrjournals.org)
  • GK, one of the four members of the hexokinase family of enzymes ( 1 , 2 , 4 , 5 ), operates as a monomer and phosphorylates glucose on carbon 6 with MgATP as the second substrate to form glucose-6-phosphate (G6P). (diabetesjournals.org)
  • GTPases are a broad family of enzymes with a wide variety of activities such as signal transduction, Ras-mediated cell signaling and endocytosis. (discoverx.com)
  • Chymotrypsin is a digestive enzyme belonging to a super family of enzymes called serine proteases. (libretexts.org)
  • Enzymes are thought to form a complex with the substrates to catalyze the reaction. (news-medical.net)
  • Plant Aldehyde Dehydrogenase10 (ALDH10) enzymes catalyze the oxidation of ω-primary or ω-quaternary aminoaldehydes, but, intriguingly, only some of them, such as the spinach ( Spinacia oleracea ) betaine aldehyde dehydrogenase (SoBADH), efficiently oxidize betaine aldehyde (BAL) forming the osmoprotectant glycine betaine (GB), which confers tolerance to osmotic stress. (plantphysiol.org)
  • These nucleases are involved in DNA repair, immune regulation, and have been associated with various diseases, including cancer and immune disorders. (uzh.ch)
  • This article will cover the basic principles of enzyme kinetics, including the reaction equation, rate of reaction and maximal velocity (V max ) and Michaelis Constant (K m ). (news-medical.net)
  • The course involves the study of the fundamental principles of chemistry with particular emphasis on the role of chemistry in our culture and everyday affairs, and the benefits and costs of chemical technology. (shepherd.edu)
  • n\nBiophysical and Medicinal Chemistry Lab sections\nLaboratory experiments involve the application of chemical principles and techniques to systems of biological and medicinal importance. (kenyon.edu)
  • www.microcalorimetry.com) is sensitive enough that enzyme requirements are similar to those of spectrophotometric assays. (genengnews.com)
  • radiometric assays involve the incorporation or release of radioactivity to measure the amount of product made over time. (academic.ru)
  • Although radiometric assays require the removal and counting of samples (i.e., they are discontinuous assays) they are usually extremely sensitive and can measure very low levels of enzyme activity. (academic.ru)
  • There are numerous assays available to measure the activity of enzymes involved in the transfer of a phosphate from ATP to a substrate macromolecule. (discoverx.com)
  • However, there are only a few assays for enzymes that utilize other nucleotide triphosphates, opening opportunities to address pharmacologically relevant targets. (discoverx.com)
  • But some mechanistic enzymologists are adopting a broader perspective, investigating not just how enzymes work individually but also how they function in the context of the cell. (acs.org)
  • Not all mechanistic enzymologists subscribe to this shift in emphasis, but the effort expended on studies of enzyme function seems to be growing. (acs.org)
  • 2006). Mechanistic Requirements for the Efficient Enzyme-Catalyzed Hydrolysis of Thiosialosides. (olisweb.com)
  • We are involved in the study of structural and mechanistic aspects of the biochemical function of various electron transfer and redox metalloenzymes using different physicochemical techniques. (tifr.res.in)
  • 6. The reagent of claim 1, wherein the reagent further comprises a buffer, the buffer having a higher oxidation potential than the reduced form of the redox mediator and being in sufficient amount to provide and maintain a pH at which the enzymecatalyzes the reaction involving enzyme, analyte, and the redox mediator. (patentgenius.com)
  • Pseudo-zero order because since most/all enzymes are filled and we have approached or reached Vmax, the reaction rate cannot increase any further and is therefore not relying on an increase in [S] to increase. (brainscape.com)
  • The several attempts made so far have had limited success, stressing the need for a better understanding of the structural and functional properties of the enzymes involved in the GB biosynthetic pathway. (plantphysiol.org)
  • In this work we have developed an alternative approach to monitor kinase activity, which involves the use of a stable luminescent europium( III ) complex, [Eu. + , that binds reversibly to ATP and ADP, providing distinctive emission spectral responses, enabling the change in ADP/ATP ratio to be dynamically followed during a kinase reaction ( Fig. 1a ). (rsc.org)
  • In the other system, two species bind once and one binds twice to the enzyme. (mysciencework.com)
  • The main focus of our lab is to understand the functional role deubiquitinating enzymes (deubiquitinases or DUBs) in cellular pathways, particularly the ones implicated in neurodegeneration (gradual loss of neurons), such as Alzheimer's disease (AD) and Parkinson's disease (PD). (purdue.edu)
  • Endonuclease G (EndoG), a member of DNA/RNA nonspecific ββα-Me-finger nucleases, is involved in apoptosis and normal cellular proliferation. (biomedcentral.com)
  • Glutamine-derived glutamate is also involved in the synthesis of the reducing equivalent glutathione, vital to maintaining cellular redox status. (aacrjournals.org)