Aspartic endopeptidase

The NC-IUBMB has introduced a number of changes in the terminology following the proposals made by Barrett, Rawlings and co-workers [7] [8]. The term peptidase should now be used as a synonym for peptide hydrolase and includes all enzymes that hydrolyze peptide bonds. Previously the term peptidases was restricted to exopeptidases . The terms peptidase and protease are now synonymous. For consistency with this nomenclature, the term proteinases has been replaced by endopeptidases . To complete this note on terminology, we remind the reader that the terms cysteine endopeptidases and aspartic endopeptidases were previously called thiol proteinases and acid or carboxyl proteinases , respectively [9],... 

Aspartic endopeptidases (EC 3.4.23) are the best-known aspartic hydrolases and the only ones to be presented here. These enzymes were formerly called acid proteinases because most of them are active at low pH. In con-... 

Aspartic endopeptidases contain two catalytically essential aspartic residues. Their postulated catalytic mechanism is summarized in Fig. 3.10 with pepsin A (EC 3.4.23.1) as an example [2] ... 

PEPTIDOMIMETIC COMPOUND PEPTIDYL-ASPARTATE ENDOPEPTIDASE Peptidylglycine,... 

This text is a good source of information on the chemical mechanisms underlying the different modes of peptidase catalysis. Three important enzymes are covered subtilisin, a serine endopepti-dase papain, a cysteine endopeptidase and chymosin, an aspartic endopeptidase. 

Du/tripeptidyl-peptidases Peptidyl-dipeptidases Serine carboxypeptidases MetaUocarboxypeptidases Cysteine carboxypeptidases Omega peptidases Serine endopeptidases Cysteine endopeptidases Aspartic endopeptidases MetaUoendopeptidases Threonine endopeptidases Other endopeptidases... 

Aspartic endopeptidase Aspartic acid (2 residues) in the active site Pepsin, cathepsin D, rennin (chymosin)... 

The group name aspartic endopeptidases indicates that the carboxyl groups of two aspartic acid residues are the catalytic groups in the active site. The best studied of this group of enzymes is pepsin (EC 3.4.23.1), but chymosin (EC 3.4.23.4) and a large number of microbial proteases also belong to this group. Pepsin has a preference for hydrolysis at the aromatic amino acid residues. 

Hiraiwa, N., Kondo, M., Nishimura, M., et al., 1997. An aspartic endopeptidase is involved in the breakdown of propeptides of storage proteins in protein-storage vacuoles of plants. Eur. J. Biochem. 246, 133-141. 

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