Reaction: a demethylmenaquinone + S-adenosyl-L-methionine = a menaquinol + S-adenosyl-L-homocysteine
For diagram of reaction click here.
Other name(s): S-adenosyl-L-methione—DMK methyltransferase; demethylmenaquinone C-methylase; 2-heptaprenyl-1,4-naphthoquinone methyltransferase; 2-demethylmenaquinone methyltransferase; S-adenosyl-L-methione:2-demethylmenaquinone methyltransferase
Systematic name: S-adenosyl-L-methione:demethylmenaquinone methyltransferase
Comments: The enzyme catalyses the last step in menaquinone biosynthesis. It is able to accept substrates with varying polyprenyl side chain length (the chain length is determined by polyprenyl diphosphate synthase)[1]. The enzyme from Escherichia coli also catalyses the conversion of 2-methoxy-6-octaprenyl-1,4-benzoquinone to 5-methoxy-2-methyl-3-octaprenyl-1,4-benzoquinone during the biosynthesis of ubiquinone [4]. The enzyme probably acts on menaquinol rather than menaquinone.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:
References:
1. Koike-Takeshita, A., Koyama, T. and Ogura, K. Identification of a novel gene cluster participating in menaquinone (vitamin K2) biosynthesis. Cloning and sequence determination of the 2-heptaprenyl-1,4-naphthoquinone methyltransferase gene of Bacillus stearothermophilus. J. Biol. Chem. 272 (1997) 12380-12383. [PMID: 9139683]
2. Wissenbach, U., Ternes, D. and Unden, G. An Escherichia coli mutant containing only demethylmenaquinone, but no menaquinone: effects on fumarate, dimethylsulfoxide, trimethylamine N-oxide and nitrate respiration. Arch. Microbiol. 158 (1992) 68-73. [PMID: 1444716]
3. Catala, F., Azerad, R. and Lederer, E. Sur les propriétés de la desméthylménaquinone C-méthylase de Mycobacterium phlei. Int. Z. Vitaminforsch. 40 (1970) 363-373. [PMID: 5450997]
4. Lee, P.T., Hsu, A.Y., Ha, H.T. and Clarke, C.F. A C-methyltransferase involved in both ubiquinone and menaquinone biosynthesis: isolation and identification of the Escherichia coli ubiE gene. J. Bacteriol. 179 (1997) 1748-1754. [PMID: 9045837]