IUBMB Enzyme Nomenclature


Accepted name: chymosin

Reaction: Broad specificity similar to that of pepsin A. Clots milk by cleavage of a single Ser-Phe105Met-Ala bond in κ-chain of casein

Other names: rennin (but this should be avoided since it leads to confusion with renin)

Comments: Neonatal gastric enzyme with high milk clotting and weak general proteolytic activity, formed from prochymosin. Found among mammals with postnatal uptake of immunoglobulins. In peptidase family A1(pepsin A family)

Links to other databases: BRENDA, EXPASY, GTD, KEGG, MEROPS, Metacyc, PDB, CAS registry number: 9001-98-3


1. Foltmann, B. A review of prorennin and rennin. C. R. Trav. Lab. Carlsberg 35 (1966) 143-231. [PMID: 5330666]

2. Harris, T.J.R., Lowe, P.A., Lyons, A., Thomas, P.G., Eaton, M.A.W., Millican, T.A., Patel, T.P., Bose, C.C., Carey, N.H. and Doel, M.T. Molecular cloning and nucleotide sequence of cDNA coding for calf preprochymosin. Nucleic Acids Res. 10 (1982) 2177-2187. [PMID: 6283469]

3. Visser, S., Slangen, C.J. and van Rooijen, P.J. Peptide substrates for chymosin (rennin). Interaction sites in κ-casein-related sequences located outside the (103-108)-hexapeptide region that fits into the enzyme's active-site cleft. Biochem. J. 244 (1987) 553-558. [PMID: 3128264]

[EC created 1961 as EC, transferred 1972 to EC, modified 1986]

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