Coenzyme B
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| Coenzyme B | |
|---|---|
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| IUPAC name | 2-[(7-mercapto-1-oxoheptyl)amino]-3-phosphonooxybutanoic acid |
| Identifiers | |
| CAS number | [104302-77-4] |
| PubChem | |
| SMILES | CC(C(C(=O)O)NC(=O)CCCCCCS)OP(=O)(O)O |
| Properties | |
| Molecular formula | C11H22NO7PS |
| Molar mass | 343.333641 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Coenzyme B is a coenzyme required for redox reactions in methanogens. The full chemical name of coenzyme B is 7-thioheptanoylthreoninephosphate.[1] The molecule contains a thiol, which is its principal site of reaction.
Coenzyme B reacts with 2-methylthioethanesulfonate, abbreviated CH3-S-CoM, to release methane in methanogenesis:[2]
- 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.
A related conversion that utilizes both HS-CoB and HS-CoM is the reduction of fumarate to succinate, catalyzed by fumarate reductase:[3]
- CH3-S-CoM + HS-CoB -O2CCH=CHCO2- → -O2CCH2-CH2CO2- + CoB-S-S-CoM
[edit] References
- ^ Noll KM, Rinehart KL, Tanner RS, Wolfe RS (1986). "Structure of component B (7-mercaptoheptanoylthreonine phosphate) of the methylcoenzyme M methylreductase system of Methanobacterium thermoautotrophicum". Proc. Natl. Acad. Sci. U.S.A. 83 (12): 4238–42. doi:. PMID 3086878.
- ^ Thauer, R. K., "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson", Microbiology, 1998, volume 144, pages 2377-2406.
- ^ Heim, S.; Künkel, A.; Thauer, R. K.; Hedderich, R. “Thiol:fumarate Reductase (Tfr) from Methanobacterium thermoautotrophicum: Identification of the Catalytic Sites for Fumarate Reduction and Thiol Oxidation” European Journal of Biochemistry 1998, volume 253, pages 292-299.
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