IUBMB Enzyme Nomenclature


Accepted name: cystathionine β-synthase (O-acetyl-L-serine)

Reaction: O-acetyl-L-serine + L-homocysteine = L-cystathionine + acetate

For diagram of reaction click here.

Other name(s): MccB; O-acetylserine dependent cystathionine β-synthase

Systematic name: O-acetyl-L-serine:L-homocysteine 2-amino-2-carboxyethyltransferase

Comments: A pyridoxal 5'-phosphate protein. The enzyme, purified from the bacterium Bacillus subtilis, also has a low activity with L-serine (cf. EC, cystathionine β-synthase).

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


1. Hullo, M.F., Auger, S., Soutourina, O., Barzu, O., Yvon, M., Danchin, A. and Martin-Verstraete, I. Conversion of methionine to cysteine in Bacillus subtilis and its regulation. J. Bacteriol. 189 (2007) 187-197. [PMID: 17056751]

[EC created 2016]

Return to EC 2.5.1 home page
Return to EC 2.5 home page
Return to EC 2 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page