EzCatDB: S00449

DB codeS00449
RLCP classification1.13.30000.44
CATH domainDomain 13.90.70.10Catalytic domain
E.C.3.4.22.25

CATH domainRelated DB codes (homologues)
3.90.70.10S00444,S00445,S00447,S00448,S00450,S00451,S00446,S00518

Enzyme Name
Swiss-protKEGG

P05994
Protein namePapaya proteinase 4glycyl endopeptidase
papaya peptidase B
papaya proteinase IV
glycine-specific proteinase
chymopapain
Papaya proteinase 4
PPIV
chymopapain M
SynonymsEC 3.4.22.25
Papaya proteinase IV
PPIV
Papaya peptidase B
Glycyl endopeptidase


Swiss-prot:Accession NumberP05994
Entry namePAPA4_CARPA
ActivityPreferential cleavage: Gly-|-Xaa, in proteins and in small molecule substrates.
Subunit
Subcellular location
Cofactor


SubstratesProductsintermediates
KEGG-idC00017C00012C00001C00017C00012I00153I00154I00155
CompoundProteinPeptideH2OProteinPeptidePeptidyl-Cys-tetrahedral-intermediate (with previous peptide)Acyl-enzyme(Peptidyl-Cys-acyl group)Peptidyl-Cys-tetrahedral-intermediate
Typepeptide/proteinpeptide/proteinH2Opeptide/proteinpeptide/protein


1gecEUnboundUnbound
UnboundUnboundUnboundIntermediate-analogue:PHQ-LEU-VAL-GLY-0HQ(chain I)Unbound

Active-site residues
resource
Swiss-prot;P05994
pdbCatalytic residuesMain-chain involved in catalysis
1gecEGLN 19;CYS 25;HIS 159;ASN 179
CYS 25

References for Catalytic Mechanism
ReferencesSectionsNo. of steps in catalysis
[1]p.814-818

references
[1]
PubMed ID8010964
JournalBiochem J
Year1994
Volume300
Pages805-20
AuthorsThomas MP, Topham CM, Kowlessur D, Mellor GW, Thomas EW, Whitford D, Brocklehurst K
TitleStructure 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.
[2]
CommentsX-ray crystallography (2.1 Angstroms)
PubMed ID7548082
JournalBiochemistry
Year1995
Volume34
Pages13190-5
AuthorsO'Hara BP, Hemmings AM, Buttle DJ, Pearl LH
TitleCrystal structure of glycyl endopeptidase from Carica papaya: a cysteine endopeptidase of unusual substrate specificity.
Related PDB1gec
Related Swiss-protP05994
[3]
PubMed ID8862553
JournalProtein Eng
Year1996
Volume9
Pages525-9
AuthorsBaker KC, Taylor MA, Cummings NJ, Tunon MA, Worboys KA, Connerton IF
TitleAutocatalytic processing of pro-papaya proteinase IV is prevented by crowding of the active-site cleft.

comments
This enzyme belongs to the peptidase family-C1.
According to the paper [1], the catalytic mechanism of this enzyme could be analogous to those in papain and other cysteine proteinases. Moreover, the Cys25/His159 ion-pair is insufficient for catalytc competence in these enzymes [1].
Considering the structural similarities to other homologous peptidases, the sidechain of Gln19 might form an oxyanion hole, together with the mainchain amide of Cys25.

createdupdated
2002-07-012012-10-23


Copyright: Nozomi Nagano, JST & CBRC-AIST
Funded by PRESTO/Japan Science and Technology Corporation (JST) (December 2001 - November 2004)
Funded by Grant-in-Aid for Publication of Scientific Research Results/Japan Society for the Promotion of Science (JSPS) (April 2005 - March 2006)
Funded by Grant-in-Aid for Scientific Research (B)/Japan Society for the Promotion of Science (JSPS) (April 2005 - March 2008)
Funded by BIRD/Japan Science and Technology Corporation (JST) (September 2005 - September 2010)
Funded by BIRD/Japan Science and Technology Corporation (JST) (October 2007 - September 2010)
Funded by Grant-in-Aid for Publication of Scientific Research Results/Japan Society for the Promotion of Science (JSPS) (April 2011 - March 2012)

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