IUBMB Enzyme Nomenclature


Accepted name: adenosylhomocysteinase

Reaction: S-adenosyl-L-homocysteine + H2O = L-homocysteine + adenosine

For diagram of reaction mechanism, click here

Other name(s): S-adenosylhomocysteine synthase; S-adenosylhomocysteine hydrolase (ambiguous); adenosylhomocysteine hydrolase; S-adenosylhomocysteinase; SAHase; AdoHcyase

Systematic name: S-adenosyl-L-homocysteine hydrolase

Comments: The enzyme contains one tightly bound NAD+ per subunit. This appears to bring about a transient oxidation at C-3' of the 5'-deoxyadenosine residue, thus labilizing the thioether bond [2] (for mechanism, click here), cf. EC, inositol-3-phosphate synthase.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, MetaCyc, CAS registry number:


1. de la Haba, G. and Cantoni, G.L. The enzymatic synthesis of S-adenosyl-L-homocysteine from adenosine and homocysteine. J. Biol. Chem. 234 (1959) 603-608. [PMID: 13641268]

2. Palmer, J.L. and Abeles, R.H. The mechanism of action of S-adenosylhomocysteinase. J. Biol. Chem. 254 (1979) 1217-1226. [PMID: 762125]

[EC created 1961 as EC, modified 2004, transferred 2022 to EC]

Return to EC 3.13.2 home page
Return to EC 3.13 home page
Return to EC 3 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page