2009_Book_FoodChemistry

1.4 Proteins 77
Table 1.33. Classification of proteolytic enzymes (peptidases)
EC-No. a Enzyme group Comments Examples
Exopeptidases Cleave proteins/peptides
stepwise from N- or C-terminals
3.4.11. Aminopeptidases Cleave amino acids from N-terminal Various aminopeptidases
3.4.13. Dipeptidases Cleave dipeptides Various dipeptidases (carnosinase, anserinase)
3.4.14. Dipeptidyl- and tripeptidylpeptidases Cleave di- and tripeptides from N-terminal Cathepsin C
3.4.15. Peptidyl-dipeptidases Cleave dipeptides from C-terminal Carboxycathepsin,
3.4.16. Serine carboxypeptidases Cleave amino acids from C-terminal, serine in the active
site
3.4.17. Metalocarboxypeptidases Cleave amino acids from C-terminal, Zn 2+ or Co 2+ in
the active site
3.4.18. Cysteine carboxypeptidases Cleave amino acids from C-terminal, cysteine in the active
site
Carboxypeptidase C, cathepsin A
Carboxypeptidases A and B
Lysosomal carboxypeptidase B
Endopeptidases Cleave protein/peptide
bonds other than terminal ones
3.4.21. Serine endopeptidase Serine in the active site Chymotrypsins A, B and C, peptidase B alkaline proteinases
α-and β-trypsin,
3.4.22. Cysteine endopeptidase Cysteine in the active site Papain, ficin, bromelain, cathepsin B
3.4.23. Aspartic endopeptidase Aspartic acid (2 residues) in the active site Pepsin, cathepsin D, rennin (chymosin)
3.4.24. Metaloendopeptidase Metal ions in the active site Collagenase, microbial neutral proteinases
a cf. 2.2.7