On the role of N‐7‐mercaptoheptanoyl‐O‐phospho‐L‐threonine (component B) in the enzymatic reduction of methyl‐coenzyme M to methane
- 17 August 1987
- journal article
- Published by Wiley in FEBS Letters
- Vol. 220 (2), 358-362
- https://doi.org/10.1016/0014-5793(87)80846-3
Abstract
The reduction of methyl-coenzyme M (CH3SCoM) to methane in methanogenic bacteria is dependent on component B (N-7-mercaptoheptanoyl-O-phospho-L-threonine, HSHTP). We report here that S-methyl-component B (N-7-(methylthio)heptanoyl-O-phospho-L-threonine, CH3SHTP) can substitute for neither CH3SCoM nor HSHTP in the methyl-CoM reductase reaction. Rather, CH3SHTP proved to be an inhibitor competitive with HSHTP (apparent Ki = 6 microM) and noncompetitive with CH3SCoM. These results make it very unlikely that HSHTP functions as a methyl group carrier. A role for HSHTP as direct electron donor for CH3SCoM reduction to CH4 is proposed.Keywords
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