Coenzyme M is a coenzyme required for methyl-transfer reactions in the metabolism of methanogens.[1][2] The coenzyme is an anion with the formula HSCH2CH2SO−
3. It is named 2-mercaptoethanesulfonate and abbreviated HS–CoM. The cation is unimportant, but the sodium salt is most available. Mercaptoethanesulfonate contains both a thiol, which is the main site of reactivity, and a sulfonate group, which confers solubility in aqueous media.
Biochemical role
The coenzyme is the C1 carrier in methanogenesis. It is converted to methyl coenzyme M, the thioether CH3SCH2CH2SO−
3, in the penultimate step to methane formation.[3] Coenzyme M reacts with coenzyme B, 7-thioheptanoylthreoninephosphate, to give a heterodisulfide, releasing methane:
- CH3–S–CoM + HS–CoB → CH4 + CoB–S–S–CoM
This conversion is catalyzed by the enzyme methyl coenzyme M reductase, which contains cofactor F430 as the prosthetic group.
References
- ^ Balch WE, Wolfe RS (1979). "Specificity and biological distribution of coenzyme M (2-mercaptoethanesulfonic acid)". J. Bacteriol. 137 (1): 256–63. PMC 218444. PMID 104960. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=218444.
- ^ Taylor CD, Wolfe RS (10 August 1974). "Structure and methylation of coenzyme M(HSCH2CH2SO3)". J. Biol. Chem. 249 (15): 4879–85. PMID 4367810. http://www.jbc.org/cgi/reprint/249/15/4879.
- ^ Thauer RK (1998). "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson". Microbiology 144 (9): 2377–2406. doi:10.1099/00221287-144-9-2377. PMID 9782487. http://mic.sgmjournals.org/cgi/pmidlookup?view=long&pmid=9782487.
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