Hydrolases
Any member of the class of enzymes that catalyze the cleavage of the substrate and the addition of water to the resulting molecules, e.g., ESTERASES, glycosidases (GLYCOSIDE HYDROLASES), lipases, NUCLEOTIDASES, peptidases (PEPTIDE HYDROLASES), and phosphatases (PHOSPHORIC MONOESTER HYDROLASES). EC 3.
Glycoside Hydrolases
Glycoside Hydrolases are a class of enzymes that catalyze the hydrolysis of glycosidic bonds, resulting in the breakdown of complex carbohydrates and oligosaccharides into simpler sugars.
Epoxide Hydrolases
Carboxylic Ester Hydrolases
Enzymes which catalyze the hydrolysis of carboxylic acid esters with the formation of an alcohol and a carboxylic acid anion.
Lysosomes
A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Acid Phosphatase
Glucuronidase
Glucuronidase is an enzyme (specifically, a glycosidase) that catalyzes the hydrolysis of glucuronic acid from various substrates, playing crucial roles in metabolic processes like detoxification and biotransformation within organisms.
Hexosaminidases
Enzymes that catalyze the hydrolysis of N-acylhexosamine residues in N-acylhexosamides. Hexosaminidases also act on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES.
Mannosephosphates
Phosphoric acid esters of mannose.
N-Acetylmuramoyl-L-alanine Amidase
An autolytic enzyme bound to the surface of bacterial cell walls. It catalyzes the hydrolysis of the link between N-acetylmuramoyl residues and L-amino acid residues in certain cell wall glycopeptides, particularly peptidoglycan. EC 3.5.1.28.
Peptide Hydrolases
Hydrolases that specifically cleave the peptide bonds found in PROTEINS and PEPTIDES. Examples of sub-subclasses for this group include EXOPEPTIDASES and ENDOPEPTIDASES.
Mucolipidoses
A group of inherited metabolic diseases characterized by the accumulation of excessive amounts of acid mucopolysaccharides, sphingolipids, and/or glycolipids in visceral and mesenchymal cells. Abnormal amounts of sphingolipids or glycolipids are present in neural tissue. INTELLECTUAL DISABILITY and skeletal changes, most notably dysostosis multiplex, occur frequently. (From Joynt, Clinical Neurology, 1992, Ch56, pp36-7)
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.
Substrate Specificity
Thiolester Hydrolases
Thiolester hydrolases are enzymes that catalyze the hydrolysis of thioester bonds, commonly found in acetyl-CoA and other coenzyme A derivatives, to produce free carboxylic acids and CoASH.
Receptor, IGF Type 2
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.
Acetylglucosaminidase
A beta-N-Acetylhexosaminidase that catalyzes the hydrolysis of terminal, non-reducing 2-acetamido-2-deoxy-beta-glucose residues in chitobiose and higher analogs as well as in glycoproteins. Has been used widely in structural studies on bacterial cell walls and in the study of diseases such as MUCOLIPIDOSIS and various inflammatory disorders of muscle and connective tissue.
alpha-L-Fucosidase
An enzyme that catalyzes the hydrolysis of an alpha L-fucoside to yield an alcohol and L-fucose. Deficiency of this enzyme can cause FUCOSIDOSIS. EC 3.2.1.51.
Xylosidases
A group of enzymes that catalyze the hydrolysis of alpha- or beta-xylosidic linkages. EC 3.2.1.8 catalyzes the endo-hydrolysis of 1,4-beta-D-xylosidic linkages; EC 3.2.1.32 catalyzes the endo-hydrolysis of 1,3-beta-D-xylosidic linkages; EC 3.2.1.37 catalyzes the exo-hydrolysis of 1,4-beta-D-linkages from the non-reducing termini of xylans; and EC 3.2.1.72 catalyzes the exo-hydrolysis of 1,3-beta-D-linkages from the non-reducing termini of xylans. Other xylosidases have been identified that catalyze the hydrolysis of alpha-xylosidic bonds.
Cellulase
An endocellulase with specificity for the hydrolysis of 1,4-beta-glucosidic linkages in CELLULOSE, lichenin, and cereal beta-glucans.
Cellvibrio
A genus of aerobic, gram-negative, motile, slightly curved, rod-shaped bacteria. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
beta-Glucosidase
An exocellulase with specificity for a variety of beta-D-glycoside substrates. It catalyzes the hydrolysis of terminal non-reducing residues in beta-D-glucosides with release of GLUCOSE.
Galactosidases
beta-Mannosidase
An enzyme that catalyzes the hydrolysis of terminal, non-reducing beta-D-mannose residues in beta-D-mannosides. The enzyme plays a role in the lysosomal degradation of the N-glycosylprotein glycans. Defects in the lysosomal form of the enzyme in humans result in a buildup of mannoside intermediate metabolites and the disease BETA-MANNOSIDOSIS.
Endo-1,4-beta Xylanases
Enzymes which catalyze the endohydrolysis of 1,4-beta-D-xylosidic linkages in XYLANS.
Acid Anhydride Hydrolases
A group of enzymes that catalyze the hydrolysis of diphosphate bonds in compounds such as nucleoside di- and tri-phosphates, and sulfonyl-containing anhydrides such as adenylylsulfate. (Enzyme Nomenclature, 1992) EC 3.6.
Arylsulfatases
Enzymes that catalyze the hydrolysis of a phenol sulfate to yield a phenol and sulfate. Arylsulfatase A, B, and C have been separated. A deficiency of arylsulfatases is one of the causes of metachromatic leukodystrophy (LEUKODYSTROPHY, METACHROMATIC). EC 3.1.6.1.
beta-N-Acetylhexosaminidases
A hexosaminidase specific for non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. It acts on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES. Two specific mammalian isoenzymes of beta-N-acetylhexoaminidase are referred to as HEXOSAMINIDASE A and HEXOSAMINIDASE B. Deficiency of the type A isoenzyme causes TAY-SACHS DISEASE, while deficiency of both A and B isozymes causes SANDHOFF DISEASE. The enzyme has also been used as a tumor marker to distinguish between malignant and benign disease.
Disaccharidases
Sequence Homology, Amino Acid
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Pyrophosphatases
A group of enzymes within the class EC 3.6.1.- that catalyze the hydrolysis of diphosphate bonds, chiefly in nucleoside di- and triphosphates. They may liberate either a mono- or diphosphate. EC 3.6.1.-.
Cathepsins
A group of lysosomal proteinases or endopeptidases found in aqueous extracts of a variety of animal tissues. They function optimally within an acidic pH range. The cathepsins occur as a variety of enzyme subtypes including SERINE PROTEASES; ASPARTIC PROTEINASES; and CYSTEINE PROTEASES.
Amidohydrolases
Amidohydrolases are enzymes that catalyze the hydrolysis of amides and related compounds, playing a crucial role in various biological processes including the breakdown and synthesis of bioactive molecules.
Mannosidases
N-Glycosyl Hydrolases
Cathepsin D
Cell Wall
Monocrotophos
Cloning, Molecular
Transferases (Other Substituted Phosphate Groups)
A class of enzymes that transfers substituted phosphate groups. EC 2.7.8.
Cellulases
A family of glycosidases that hydrolyse crystalline CELLULOSE into soluble sugar molecules. Within this family there are a variety of enzyme subtypes with differing substrate specificities that must work together to bring about complete cellulose hydrolysis. They are found in structures called CELLULOSOMES.
Catalytic Domain
Esterases
Esterases are hydrolase enzymes that catalyze the hydrolysis of ester bonds, converting esters into alcohols and acids, playing crucial roles in various biological processes including metabolism and detoxification.
Vacuoles
Sequence Alignment
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Catalysis
Cellulose
A polysaccharide with glucose units linked as in CELLOBIOSE. It is the chief constituent of plant fibers, cotton being the purest natural form of the substance. As a raw material, it forms the basis for many derivatives used in chromatography, ion exchange materials, explosives manufacturing, and pharmaceutical preparations.
Hydrogen-Ion Concentration
Saposins
A group of four homologous sphingolipid activator proteins that are formed from proteolytic cleavage of a common protein precursor molecule referred to as prosaposin.
Acetylesterase
Cellulose 1,4-beta-Cellobiosidase
An exocellulase with specificity for the hydrolysis of 1,4-beta-D-glucosidic linkages in CELLULOSE and cellotetraose. It catalyzes the hydrolysis of terminal non-reducing ends of beta-D-glucosides with release of CELLOBIOSE.
Sulfatases
Sulfatases are a group of enzymes that catalyze the hydrolysis of sulfate ester bonds in various substrates, playing crucial roles in the metabolism and homeostasis of carbohydrates, proteoglycans, neurotransmitters, and steroid hormones within the body.
Models, Molecular
Sucrase
'Sucrase' is an intestinal brush-border enzyme that catalyzes the hydrolysis of sucrose into glucose and fructose in the digestive process.
Sterol Esterase
An enzyme that catalyzes the hydrolysis of CHOLESTEROL ESTERS and some other sterol esters, to liberate cholesterol plus a fatty acid anion.
Phosphoric Monoester Hydrolases
A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate. EC 3.1.3.
Glucans
alpha-Mannosidase
An enzyme that catalyzes the HYDROLYSIS of terminal, non-reducing alpha-D-mannose residues in alpha-D-mannosides. The enzyme plays a role in the processing of newly formed N-glycans and in degradation of mature GLYCOPROTEINS. There are multiple isoforms of alpha-mannosidase, each having its own specific cellular location and pH optimum. Defects in the lysosomal form of the enzyme results in a buildup of mannoside intermediate metabolites and the disease ALPHA-MANNOSIDOSIS.
alpha-Glucosidases
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.
Cathepsin A
A carboxypeptidase that catalyzes the release of a C-terminal amino acid with a broad specificity. It also plays a role in the LYSOSOMES by protecting BETA-GALACTOSIDASE and NEURAMINIDASE from degradation. It was formerly classified as EC 3.4.12.1 and EC 3.4.21.13.
Oligosaccharides
Crystallography, X-Ray
Palmitoyl-CoA Hydrolase
Enzyme catalyzing reversibly the hydrolysis of palmitoyl-CoA or other long-chain acyl coenzyme A compounds to yield CoA and palmitate or other acyl esters. The enzyme is involved in the esterification of fatty acids to form triglycerides. EC 3.1.2.2.
Neocallimastigales
An order of fungi in the phylum NEOCALLIMASTIGOMYCOTA comprising anaerobic chytrids that inhabit the RUMEN; and CECUM of herbivorous animals. Genera (all in the lone family Neocallimastigaceae) include NEOCALLIMASTIX, Orpinomyces, PIROMYCES, Anaeromyces, Cyllamyces, and Caecomyces.
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.
Alteromonas
Aspartylglucosylaminase
An enzyme that catalyzes the conversion of N(4)-(beta-N-acetyl-D-glucosaminyl)-L-asparagine and water to N-acetyl-beta-D-glucosaminylamine and L-aspartate. It acts only on asparagine-oligosaccharides containing one amino acid, i.e. the ASPARAGINE has free alpha-amino and alpha-carboxyl groups. (From Enzyme Nomenclature, 1992)
Fibrobacter
A genus of gram-negative, anaerobic bacteria in the family Fibrobacteraceae, isolated from the human GASTROINTESTINAL TRACT.
Glucan Endo-1,3-beta-D-Glucosidase
An endocellulase with specificity for the hydrolysis of 1,3-beta-D-glucosidic linkages in 1,3-beta-D-glucans including laminarin, paramylon, and pachyman.
Phosphoric Diester Hydrolases
A class of enzymes that catalyze the hydrolysis of one of the two ester bonds in a phosphodiester compound. EC 3.1.4.
Epoxy Compounds
Sequence Analysis, DNA
Bacteriolysis
Carboxylesterase
Carboxylesterase is a serine-dependent esterase with wide substrate specificity. The enzyme is involved in the detoxification of XENOBIOTICS and the activation of ester and of amide PRODRUGS.
Peptidoglycan
Peptidoglycan is a complex, cross-linked polymer of carbohydrates and peptides that forms the rigid layer of the bacterial cell wall, providing structural support and protection while contributing to the bacterium's susceptibility or resistance to certain antibiotics.
Binding Sites
Glucan 1,4-beta-Glucosidase
An exocellulase with specificity for the hydrolysis of 1,4-beta-glucosidic linkages of 1,4-beta-D-glucans resulting in successive removal of GLUCOSE units.
Piromyces
A genus of fungi in the family Neocallimasticaceae, order NEOCALLIMASTICALES, containing uniflagellate zoospores.
Polysaccharides
Polysaccharides are complex carbohydrates consisting of long, often branched chains of repeating monosaccharide units joined together by glycosidic bonds, which serve as energy storage molecules (e.g., glycogen), structural components (e.g., cellulose), and molecular recognition sites in various biological systems.
Chitinase
Chitinase is an enzyme that catalyzes the hydrolysis of chitin, a polysaccharide that makes up the exoskeleton of insects and the cell walls of fungi, into simpler sugars.
Glycosyltransferases
Enzymes that catalyze the transfer of glycosyl groups to an acceptor. Most often another carbohydrate molecule acts as an acceptor, but inorganic phosphate can also act as an acceptor, such as in the case of PHOSPHORYLASES. Some of the enzymes in this group also catalyze hydrolysis, which can be regarded as transfer of a glycosyl group from the donor to water. Subclasses include the HEXOSYLTRANSFERASES; PENTOSYLTRANSFERASES; SIALYLTRANSFERASES; and those transferring other glycosyl groups. EC 2.4.
Carboxypeptidases
Ubiquitin Thiolesterase
Base Sequence
Leucyl Aminopeptidase
A zinc containing enzyme of the hydrolase class that catalyzes the removal of the N-terminal amino acid from most L-peptides, particularly those with N-terminal leucine residues but not those with N-terminal lysine or arginine residues. This occurs in tissue cell cytosol, with high activity in the duodenum, liver, and kidney. The activity of this enzyme is commonly assayed using a leucine arylamide chromogenic substrate such as leucyl beta-naphthylamide.
Endopeptidases
A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.
Cathepsin B
A lysosomal cysteine proteinase with a specificity similar to that of PAPAIN. The enzyme is present in a variety of tissues and is important in many physiological and pathological processes. In pathology, cathepsin B has been found to be involved in DEMYELINATION; EMPHYSEMA; RHEUMATOID ARTHRITIS, and NEOPLASM INVASIVENESS.
Trichoderma
A mitosporic fungal genus frequently found in soil and on wood. It is sometimes used for controlling pathogenic fungi. Its teleomorph is HYPOCREA.
Sphingolipid Activator Proteins
Hexosephosphates
Carbohydrate Metabolism
Cellular processes in biosynthesis (anabolism) and degradation (catabolism) of CARBOHYDRATES.
Gold Colloid, Radioactive
A suspension of radioactive gold particles emitting negative beta particles and gamma irradiation. It was formerly used for liver scans and irradiation treatment of some metastatic malignancies.
Acidianus
A genus of facultatively anaerobic coccoid ARCHAEA, in the family SULFOLOBACEAE. Cells are highly irregular in shape and thermoacidophilic. Lithotrophic growth occurs aerobically via sulfur oxidation in some species. Distribution includes solfataric springs and fields, mudholes, and geothermically heated acidic marine environments.
Mannose
A hexose or fermentable monosaccharide and isomer of glucose from manna, the ash Fraxinus ornus and related plants. (From Grant & Hackh's Chemical Dictionary, 5th ed & Random House Unabridged Dictionary, 2d ed)
Comamonadaceae
Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
A subclass of exopeptidases that includes enzymes which cleave either two or three AMINO ACIDS from the end of a peptide chain.
Subcellular Fractions
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
Aminopeptidases
beta-Galactosidase
A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.
Cytophaga
A genus of gram-negative gliding bacteria found in SOIL; HUMUS; and FRESHWATER and marine habitats.
Lipase
Mutation
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.
Ruminococcus
A genus of gram-positive bacteria in the family Lachnospiraceae that inhabits the RUMEN; LARGE INTESTINE; and CECUM of MAMMALS.
Cellulosomes
Extracellular structures found in a variety of microorganisms. They contain CELLULASES and play an important role in the digestion of CELLULOSE.
Sucrase-Isomaltase Complex
Acidithiobacillus thiooxidans
A strictly autotrophic species of bacteria that oxidizes sulfur and thiosulfate to sulfuric acid. It was formerly called Thiobacillus thiooxidans.
Pectins
High molecular weight polysaccharides present in the cell walls of all plants. Pectins cement cell walls together. They are used as emulsifiers and stabilizers in the food industry. They have been tried for a variety of therapeutic uses including as antidiarrheals, where they are now generally considered ineffective, and in the treatment of hypercholesterolemia.
Chitin
A linear polysaccharide of beta-1->4 linked units of ACETYLGLUCOSAMINE. It is the second most abundant biopolymer on earth, found especially in INSECTS and FUNGI. When deacetylated it is called CHITOSAN.
Cell Fractionation
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
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).
alpha-Amylases
Enzymes that catalyze the endohydrolysis of 1,4-alpha-glycosidic linkages in STARCH; GLYCOGEN; and related POLYSACCHARIDES and OLIGOSACCHARIDES containing 3 or more 1,4-alpha-linked D-glucose units.
Coriolaceae
A family of fungi, order POLYPORALES, found on decaying wood.
Monoacylglycerol Lipases
An enzyme that catalyzes the hydrolysis of glycerol monoesters of long-chain fatty acids EC 3.1.1.23.
Pinocytosis
The engulfing of liquids by cells by a process of invagination and closure of the cell membrane to form fluid-filled vacuoles.
Models, Chemical
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.
Gram-Negative Anaerobic Straight, Curved, and Helical Rods
A group of anaerobic, rod-shaped bacteria that show up as pink (negative) when treated by the Gram-staining method.
Naphthaleneacetic Acids
Enzymes
Endocytosis
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
Multigene Family
A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)
Electrophoresis, Polyacrylamide Gel
Cell Compartmentation
A partitioning within cells due to the selectively permeable membranes which enclose each of the separate parts, e.g., mitochondria, lysosomes, etc.
Mutagenesis, Site-Directed
Vesicular Transport Proteins
A broad category of proteins involved in the formation, transport and dissolution of TRANSPORT VESICLES. They play a role in the intracellular transport of molecules contained within membrane vesicles. Vesicular transport proteins are distinguished from MEMBRANE TRANSPORT PROTEINS, which move molecules across membranes, by the mode in which the molecules are transported.
Aspergillus oryzae
Arabinose
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.
Protein Structure, Secondary
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Gangliosidoses
A group of autosomal recessive lysosomal storage disorders marked by the accumulation of GANGLIOSIDES. They are caused by impaired enzymes or defective cofactors required for normal ganglioside degradation in the LYSOSOMES. Gangliosidoses are classified by the specific ganglioside accumulated in the defective degradation pathway.
Xylan Endo-1,3-beta-Xylosidase
A xylosidase that catalyses the random hydrolysis of 1,3-beta-D-xylosidic linkages in 1,3-beta-D-xylans.
alpha-Galactosidase
An enzyme that catalyzes the hydrolysis of terminal, non-reducing alpha-D-galactose residues in alpha-galactosides including galactose oligosaccharides, galactomannans, and galactolipids.
Golgi Apparatus
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Microscopy, Electron
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Alkaline Phosphatase
Endosomes
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
Protein Processing, Post-Translational
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
Naphthol AS D Esterase
Hydrolytic enzyme activity used as a histocytochemical test for the presence of esterases in tissue. Substrate used is 3-hydroxy-4'-nitro-2-naphthanilide chloroacetate (naphthol AS-D).
Biocatalysis
The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.
Adenosylhomocysteinase
Liver
Ureohydrolases
Ureohydrolases are a class of enzymes that catalyze the hydrolysis of urea into ammonia and carbon dioxide, which can include urease, urease accessory proteins, and other enzymes with similar functions.
Clostridium thermocellum
Neocallimastix
A genus of fungi in the family Neocallimasticaceae, order NEOCALLIMASTIGALES. They contain polyflagellate zoospores and grow on a range of simple and complex carbohydrates in the rumen of sheep and cattle.
Uridine Diphosphate Sugars
Genes, Bacterial
The functional hereditary units of BACTERIA.
Molecular Structure
Glucan 1,3-beta-Glucosidase
An exocellulase with specificity for 1,3-beta-D-glucasidic linkages. It catalyzes hydrolysis of beta-D-glucose units from the non-reducing ends of 1,3-beta-D-glucans, releasing GLUCOSE.
Cathepsin L
A ubiquitously-expressed cysteine protease that plays an enzymatic role in POST-TRANSLATIONAL PROTEIN PROCESSING of proteins within SECRETORY GRANULES.
Mononuclear Phagocyte System
Mononuclear cells with pronounced phagocytic ability that are distributed extensively in lymphoid and other organs. It includes MACROPHAGES and their precursors; PHAGOCYTES; KUPFFER CELLS; HISTIOCYTES; DENDRITIC CELLS; LANGERHANS CELLS; and MICROGLIA. The term mononuclear phagocyte system has replaced the former reticuloendothelial system, which also included less active phagocytic cells such as fibroblasts and endothelial cells. (From Illustrated Dictionary of Immunology, 2d ed.)
Conserved Sequence
Bacteria
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
Carbohydrates
The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.
Plants
Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.
Ribonucleases
Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.
Protein Binding
Solubility
Structure-Activity Relationship
Mannans
Polysaccharides consisting of mannose units.
Chromatography, Ion Exchange
Centrifugation, Zonal
Centrifugation using a rotating chamber of large capacity in which to separate cell organelles by density-gradient centrifugation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Dinucleoside Phosphates
Saccharomyces cerevisiae
Fungi
A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.
Sequence Homology
The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.
Bacillus
Carbohydrate Sequence
Proteins
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
Muramidase
A basic enzyme that is present in saliva, tears, egg white, and many animal fluids. It functions as an antibacterial agent. The enzyme catalyzes the hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrin. EC 3.2.1.17.
Stereoisomerism
O-Acetyl-ADP-Ribose
An acetyl ester of ADENOSINE DIPHOSPHATE RIBOSE formed during NAD-dependent deacetylation of proteins by SIRTUINS. The acetate group resides on the ribose ring where nicotinamide was cleaved from NAD during the reaction. Several isomers of O-acetyl-ADP-ribose have been isolated from the reaction.
Centrifugation, Density Gradient
Organophosphorus Compounds
Clostridium
A genus of motile or nonmotile gram-positive bacteria of the family Clostridiaceae. Many species have been identified with some being pathogenic. They occur in water, soil, and in the intestinal tract of humans and lower animals.
Biological Transport
Penicillin Amidase
An enzyme catalyzing the hydrolysis of penicillin to penicin and a carboxylic acid anion. EC 3.5.1.11.
Lysosomal Storage Diseases
Arabidopsis
A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.
Organelles
Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Ceroid
Open Reading Frames
Sucrose
A nonreducing disaccharide composed of GLUCOSE and FRUCTOSE linked via their anomeric carbons. It is obtained commercially from SUGARCANE, sugar beet (BETA VULGARIS), and other plants and used extensively as a food and a sweetener.
Gene Library
A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.
Sphingomonas
A genus of gram-negative, aerobic, rod-shaped bacteria characterized by an outer membrane that contains glycosphingolipids but lacks lipopolysaccharide. They have the ability to degrade a broad range of substituted aromatic compounds.