EC - O-acetylhomoserine aminocarboxypropyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
O-acetylhomoserine aminocarboxypropyltransferase
Other names:
O-acetyl-L-homoserine acetate-lyase (adding methanethiol)
O-acetyl-L-homoserine sulfhydrolase
O-acetylhomoserine (thiol)-lyase
O-acetylhomoserine sulfhydrolase
methionine synthase
Systematic name:
O-acetyl-L-homoserine:methanethiol 3-amino-3-carboxypropyltransferase



Also reacts with other thiols and H2S, producing homocysteine or thioethers. The name methionine synthase is more commonly applied to EC, 5-methyltetrahydrofolate-homocysteine S-methyltransferase. The enzyme from baker's yeast can also catalyse the reaction of EC, cysteine synthase, but more slowly.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Protein domains and families: PROSITE:PDOC00677
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003961
CAS Registry Number: 37290-90-7


  1. Kerr, D.
    O-Acetylhomoserine sulfhydrylase (Neurospora).
    Methods Enzymol. 17B : 446-450 (1971).
  2. Smith, I.K. and Thompson, J.F.
    Utilization of S-methylcysteine and methylmercaptan by methionineless mutants of Neurospora and the pathway of their conversion to methionine. II. Enzyme studies.
    Biochim. Biophys. Acta 184 : 130-138 (1969). [PMID: 5791104]
  3. Yamagata, S. and Takeshima, K.
    O-Acetylserine and O-acetylhomoserine sulfhydrylase of yeast. Further purification and characterization as a pyridoxal enzyme.
    J. Biochem. (Tokyo) 80 : 777-785 (1976). [PMID: 795806]
  4. Yamagata, S.
    O-Acetylserine and O-acetylhomoserine sulfhydrylase of yeast. Subunit structure.
    J. Biochem. (Tokyo) 80 : 787-797 (1976). [PMID: 795807]
  5. Yamagata, S., Takeshima, K. and Naikai, N.
    Evidence for the identity of O-acetylserine sulfhydrylase with O-acetylhomoserine sulfhydrylase in yeast.
    J. Biochem. (Tokyo) 75 : 1221-1229 (1974). [PMID: 4609980]
  6. Yamagata, S.
    Roles of O-acetyl-L-homoserine sulfhydrylases in micro-organisms.
    Biochimie 71 : 1125-1143 (1989). [PMID: 2517474]
  7. Shimizu, H., Yamagata, S., Masui, R., Inoue, Y., Shibata, T., Yokoyama, S., Kuramitsu, S. and Iwama, T.
    Cloning and overexpression of the oah1 gene encoding O-acetyl-L-homoserine sulfhydrylase of Thermus thermophilus HB8 and characterization of the gene product.
    Biochim. Biophys. Acta 1549 : 61-72 (2001). [PMID: 11566369]

[EC created 1972 as EC, transferred 2002 to EC]