EC - Sterol 24-C-methyltransferase

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IntEnz Enzyme Nomenclature


Accepted name:
sterol 24-C-methyltransferase
Other names:
24-sterol C-methyltransferase
S-adenosyl-4-methionine:sterol Δ24-methyltransferase
S-adenosyl-L-methionine:Δ24(23)-sterol methyltransferase
Δ24-sterol methyltransferase
phytosterol methyltransferase
Systematic name:
S-adenosyl-L-methionine:zymosterol 24-C-methyltransferase




Requires glutathione. Acts on a range of sterols with a 24(25)-double bond in the sidechain. While zymosterol is the preferred substrate it also acts on desmosterol, 5α-cholesta-7,24-dien-3β-ol, 5α-cholesta-5,7,24-trien-3β-ol, 4α-methylzymosterol and others. S-Adenosyl-L-methionine attacks the Si-face of the 24(25) double bond and the C-24 hydrogen is transferred to C-25 on the Re face of the double bond.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0003838
CAS Registry Number: 37257-07-1
UniProtKB/Swiss-Prot: (13) [show] [UniProt]


  1. Moore, J.T., Jr. and Gaylor, J.L.
    Isolation and purification of an S-adenosylmethionine:Δ24-sterol methyltransferase from yeast.
    J. Biol. Chem. 244 : 6334-6340 (1969). [PMID: 5354959]
  2. Venkatramesh, M., Guo, D., Jia, Z. and Nes, W.D.
    Mechanism and structural requirements for transformations of substrates by the S-adenosyl-L-methionine:Δ24(25)-sterol methyl transferase enzyme from Saccharomyces cerevisiae.
    Biochim. Biophys. Acta 1299 : 313-324 (1996). [PMID: 8597586]
  3. Tong, Y., McCourt, B.S., Guo, D., Mangla, A.T., Zhou, W.X., Jenkins, M.D., Zhou, W., Lopez, M. and Nes, W.D.
    Stereochemical features of C-methylation on the path to Δ24(28)-methylene and Δ24(28)-ethylidene sterols: studies on the recombinant phytosterol methyl transferase from Arabidopsis thaliana.
    Tetrahedron Lett. 38 : 6115-6118 (1997).
  4. Bouvier-Navé, P., Husselstein, T. and Benveniste, P.
    Two families of sterol methyltransferases are involved in the first and the second methylation steps of plant biosynthesis.
    Eur. J. Biochem. 256 : 88-96 (1998). [PMID: 9746350]
  5. Nes, W.D., McCourt, B.S., Zhou, W., Ma, J., Marshall, J.A., Peek, L.A. and Brennan, M.
    Overexpression, purification, and stereochemical studies of the recombinant S-adenosyl-L-methionine:Δ24(25)- to Δ24(28)-sterol methyl transferase enzyme from Saccharomyces cerevisiae sterol methyl transferase.
    Arch. Biochem. Biophys. 353 : 297-311 (1998). [PMID: 9606964]

[EC created 1972, modfied 2001]