IUBMB Enzyme Nomenclature


Accepted name: cystinyl aminopeptidase

Reaction: Release of an N-terminal amino acid, CysXaa-, in which the half-cystine residue is involved in a disulfide loop, notably in oxytocin or vasopressin. Hydrolysis rates on a range of aminoacyl arylamides exceed that for the cystinyl derivative, however [4]

Other names: cystyl-aminopeptidase; oxytocinase; cystine aminopeptidase; L-cystine aminopeptidase; oxytocin peptidase; vasopresssinase

Comments: A zinc-containing sialoglycoprotein In peptidase family M1 (membrane alanyl aminopeptidase family)

Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, CAS registry number: 9031-41-8


1. Sjöholm, I. Biochemical studies on oxytocin and oxytocinase. Acta Pharm. Suec. 4 (1967) 81-96. [PMID: 6041057]

2. Sjöholm, I. and Yman, L. Degradation of oxytocin, lysine vasopressin, angiotensin II, and angiotensin II amide by oxytocinase (cystine aminopeptidase). Acta Pharm. Suec. 4 (1967) 65-76. [PMID: 4292447]

3. Yman, L. Studies on human serum aminopeptidase. Some properties of oxytocinase, human serum aminopeptidase A and leucine aminopeptidase and their purification from retroplacental serum. Acta Pharm. Suec. 7 (1970) 75-86. [PMID: 5421622]

4. Sakura, H., Lin, T.Y., Doi, M., Mizutani, S. and Kawashima, Y. Purification and properties of oxytocinase, a metalloenzyme. Biochem. Int. 2 (1981) 173-179

[EC created 1972]

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