Summary for peptidase A01.006: chymosin

Summary Gene structure Alignment Tree Sequences Sequence features Distribution Structure Literature Human EST Mouse EST Substrates Inhibitors

 

Names
MEROPS Namechymosin
Other nameschymosin A, chymosin B, chymosin C, rennet, rennin
Name and HistoryChymosin is an endopeptidase that clots milk. Clotting of milk requires cleavage of kappa casein at a Phe+Met bond. Chymosin is secreted in the stomach as a proenzyme and activated by acidic pH (Pedersen et al., 1979). Production of chymosin declines after weaning (Foltmann et al., 1995). The enzyme has been used as 'rennet' in cheese making since prehistoric times, and was formerly known as 'rennin'. Chymosin is absent in human and other primates except New World monkeys (Henschel et al., 1987).
Domain architecture
MEROPS Classification
Classification Clan AA >> Subclan (none) >> Family A1 >> Subfamily A >> A01.006
Holotypechymosin (Bos taurus), Uniprot accession P00794 (peptidase unit: 61-381), MERNUM MER0000904
History Identifier created: Handbook of Proteolytic Enzymes (1998) Academic Press, London.
Activity
Catalytic typeAspartic
PeplistIncluded in the Peplist with identifier PL00004
NC-IUBMBSubclass 3.4 (Peptidases) >> Sub-subclass 3.4.23 (Aspartic endopeptidases) >> Peptidase 3.4.23.4
EnzymologyBRENDA database
Proteolytic eventsCutDB database (9 cleavages)
Activity statushuman: inactive (inactive (pseudogene) )
mouse: putative
BiotechnologyUsed in natural and recombinant forms in the making of cheese (Hayes et al., 2002).
PhysiologyPerforms limited digestion of kappa-casein in neonatal gastric digestion in ungulate mammals (Trujillo et al., 1998). The human prochymosin pseudogene is on chromosome 1.
Other databases WIKIPEDIAhttp://en.wikipedia.org/wiki/Chymosin
Cleavage site specificity Explanations of how to interpret the following cleavage site sequence logo and specificity matrix can be found here.
Cleavage patternhp/lp/se/FScissile bondml/a/i/p (based on 20 cleavages)
weblogo
Specificity matrix
 
Amino acid P4 P3 P2 P1 P1' P2' P3' P4'
Gly 0 1 1 0 0 1 0 0
Pro 4 4 1 0 0 1 0 8
Ala 0 0 0 1 0 8 1 0
Val 2 1 0 1 0 1 0 0
Leu 2 7 0 2 4 1 3 1
Ile 0 2 0 0 1 1 7 0
Met 0 0 0 0 5 0 1 0
Phe 0 0 0 14 3 0 1 1
Tyr 0 0 0 2 1 0 1 1
Trp 0 0 0 0 0 0 0 1
Ser 0 0 9 0 1 0 3 0
Thr 1 1 1 0 0 0 0 1
Cys 0 0 0 0 0 0 0 1
Asn 2 1 0 0 0 0 0 0
Gln 1 0 2 0 0 3 0 1
Asp 0 0 1 0 2 0 1 2
Glu 0 2 3 0 0 1 1 0
Lys 0 0 1 0 0 1 1 1
Arg 1 1 1 0 1 2 0 0
His 6 0 0 0 0 0 0 0
Mouse genetics
Gene symbol Position Megabases Ensembl Entrez gene MGI
Cym 3:F2.3 ENSMUSG00000046213 229697 MGI:2684977