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An enzyme that acts upon the centrally located peptide bonds of a protein molecule.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



an enzyme of the class of hydrolases. Endo-peptidases catalyze the decomposition of internal peptide bonds in proteins and peptides. The speed of hydrolysis of a given peptide bond by different endopeptidases depends on the substrate specificity of the enzyme and the spatial accessibility of the given peptide bond, especially if the substrate is a native, not denatured, protein. It does not depend on the size of the molecules of the substrate, that is, the length of the polypeptide chain. The substrate specificity of an endopeptidase consists in the ability of a given enzyme to hydrolyze the peptide bonds between certain amino acid residues with the greatest speed. For example, chy-motrypsin very rapidly hydrolyzes peptide bonds together with aromatic amino acids; trypsin does the same with diamino acids. Endopeptidases are classified as extracellular or intracellular (tissular). Extracellular endopeptidases are secreted into the digestive cavity of animals (for example, enterokinase) or simply into the external environment (the exo-enzymes of bacteria).

The use of endopeptidases in determining the primary structure of proteins is based on their properties.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The application of proline-specific endoproteinases (i.e., Brewers Clarex[R], DSM, France) that target on the degradation of haze-active proteins (i.e., hordeins) reduces the formation of storage haze in final beer product.
For the proteolysis, we used Glu-C endoproteinase from Staphylococcus aureus V8, which cleaves proteins C-terminally from Glu residues.
Abbreviations: CNBr, cyanogen bromide; Lys-C, endoproteinase Lys-C; MS, mass spectrometry; OCC, oral cavity cancer; RPLC-MS, reverse phase liquid chromatography-mass spectrometry; SCX, strong cation exchange chromatography.
Peptides with endoproteinase Arg-C digestion in at least one of the termini were considered, with 2 missed cleavages allowed.
Native lectin protein (0.5 mg) was reduced by dithiothreitol, S-carbox-amidom ethylated and digested with endoproteinase C (substrate:enzyme = 50:1, w/w) in 40 [micro]l of 10 mM Tris- HCl (pH 7.5) at 37[degrees]C for 2 h.
Peptide mapping and evaluation of glycopeptide microheterogeneity derived from endoproteinase digestion of erythropoietin by affinity high-performance capillary electrophoresis.
Next, the hemolysate is incubated with the endoproteinase Glu-C for 18 hours at 37[degrees]C to cleave Hb into peptides, whereby the specific glycated and non-glycated N-terminal peptides of the [beta]-chain of Hb are measured by either capillary electrophoresis or electrospray ionization mass spectrometry.
Amin I, Jinap S, Jamilah B (1998) Proteolytic activity (aspartic endoproteinase and carboxypeptidase) of cocoa bean during fermentation.
The [sup.32]P[O.sub.4]-labeled sample was then subjected to proteolytic digestion with endoproteinase Asp-N, which cleaves at aspartic acid residues, or aminopeptidase I, which nonspecifically removes amino acid residues inwards from N-terminus, for I hour at room temperature and followed by immunoprecipitation.
Foliar chips were incubated for 48 h in 0.5 ml of phosphate buffer (0.05 M, pH 7.5) that contained 1.95 units of carboxypeptidase B (Sigma), 2 units of endoproteinase glu-C (Boehringer-Mannheim), or 1.5 units of subtilisin (Boehringer-Mannheim).
For digestion, 2.5 [micro]L of serum was diluted with 50 [micro]L of digestion buffer; the digestion buffer contained 25 mmol/L Tris-HCl pH 7.4, 10 mmol/L dithiothreitol, 9.5 [micro]mol/L isotopic peptide internal calibrator [purified synthetic peptide, amino acid sequence RQIKKQTALVE with isotopic L-leucine (13C6, 15 N) incorporated at position 9, synthetized by Primm Biotech], and 0.1 g/L glutamyl endoproteinase (Worthington Biochemical).
LF endoproteinase activity was quantified by using mass spectrometry (3).