EC - 5-methyltetrahydropteroyltriglutamate—homocysteine S-methyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
5-methyltetrahydropteroyltriglutamate—homocysteine S-methyltransferase
Other names:
cobalamin-independent methionine synthase
homocysteine methylase
methionine synthase (cobalamin-independent)
methyltetrahydropteroylpolyglutamate:homocysteine methyltransferase
methyltransferase, tetrahydropteroylglutamate—homocysteine transmethylase
tetrahydropteroyltriglutamate methyltransferase
tetrahydropteroylglutamate-homocysteine transmethylase
Systematic name:
5-methyltetrahydropteroyltri-L-glutamate:L-homocysteine S-methyltransferase




Requires phosphate and contains zinc. The enzyme from Escherichia coli also requires a reducing system. Unlike EC, methionine synthase, this enzyme does not contain cobalamin.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003871
CAS Registry Number: 9068-29-5
UniProtKB/Swiss-Prot: (276) [show] [UniProt]


  1. Guest, J.R., Friedman, S., Foster, M.A., Tejerina, G. and Woods, D.D.
    Transfer of the methy grouup from N5-methyltetrahydrofolates to homocysteine in Escherichia coli.
    Biochem. J. 92: 497-504 (1964).
  2. Whitfield, C.D., Steers, E.J., Jr. and Weissbach, H.
    Purification and properties of 5-methyltetrahydropteroyltriglutamate-homocysteine transmethylase.
    J. Biol. Chem. 245: 390-401 (1970). [PMID: 4904482]
  3. Eichel, J., Gonzalez, J.C., Hotze, M., Matthews, R.G. and Schroder, J.
    Vitamin B12-independent methionine synthase from a higher-plant (Catharanthus roseus) - molecular characterization, regulation, heterologous expression, and enzyme properties.
    Eur. J. Biochem. 230: 1053-1058 (1995). [PMID: 7601135]
  4. Gonzalez, J.C., Peariso, K., PennerHahn, J.E. and Matthews, R.G.
    Cobalamin-independent methionine synthase from Escherichia coli: A zinc metalloenzyme.
    Biochemistry 35: 12228-12234 (1996). [PMID: 8823155]
  5. Peariso, K., Goulding, C.W., Huang, S., Matthews, R.G. and Penner-Hahn, J.E.
    Characterization of the zinc binding site in methionine synthase enzymes of Escherichia coli: The role of zinc in the methylation of homocysteine.
    J. Am. Chem. Soc. 120: 8410-8416 (1998).

[EC created 1972, modified 2003]