DB code: S00446

RLCP classification 1.13.30000.44 : Hydrolysis
CATH domain : Cathepsin B; Chain A Catalytic domain

CATH domain Related DB codes (homologues) : Cathepsin B; Chain A S00444 S00445 S00447 S00448 S00449 S00450 S00451 S00518

Uniprot Enzyme Name
UniprotKB Protein name Synonyms MEROPS Pfam
P14080 Chymopapain
Papaya proteinase II
I29.003 ()
PF08246 (Inhibitor_I29)
PF00112 (Peptidase_C1)
[Graphical View]

KEGG enzyme name
chymopapain A
chymopapain B
chymopapain S

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P14080 PAPA2_CARPA Specificity similar to that of papain.

KEGG Pathways
Map code Pathways E.C.

Compound table
Substrates Products Intermediates
KEGG-id C00017 C00012 C00001 C00017 C00012
Compound Protein Peptide H2O Protein Peptide
Type peptide/protein peptide/protein H2O peptide/protein peptide/protein
ChEBI 15377
PubChem 962
1yalA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1yalA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain GLN 19;HIS 159;ASN 179 SCH 25 (methylated CYS)

References for Catalytic Mechanism
References Sections No. of steps in catalysis

Medline ID
PubMed ID 8010964
Journal Biochem J
Year 1994
Volume 300
Pages 805-20
Authors Thomas MP, Topham CM, Kowlessur D, Mellor GW, Thomas EW, Whitford D, Brocklehurst K
Title Structure of chymopapain M the late-eluted chymopapain deduced by comparative modelling techniques and active-centre characteristics determined by pH-dependent kinetics of catalysis and reactions with time-dependent inhibitors: the Cys-25/His-159 ion-pair is insufficient for catalytic competence in both chymopapain M and papain.
Related PDB
Related UniProtKB
Comments X-ray crystallography (1.7 Angstroms)
Medline ID
PubMed ID 8973203
Journal Biochemistry
Year 1996
Volume 35
Pages 16292-8
Authors Maes D, Bouckaert J, Poortmans F, Wyns L, Looze Y
Title Structure of chymopapain at 1.7 A resolution.
Related PDB 1yal
Related UniProtKB

This enzyme belongs to the peptidase family-C1.
The paper [2] annotated the catalytic residues as Cys25, His159, and Asn179. Moreover, the active site can be superimposed onto other cysteine protease, such as cathepsin B, which suggests that Gln19 might form an oxyanion hole together with mainchan amide of Cys25.

Created Updated
2002-07-01 2009-02-26