Coenzyme B
| Names | |
|---|---|
| IUPAC name 2-[(7-mercapto-1-oxoheptyl)amino]-3-phosphonooxybutanoic acid | |
| Identifiers | |
| 3D model (JSmol) | |
| ChemSpider | |
| PubChem CID | |
| UNII | |
| CompTox Dashboard (EPA) | |
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| Properties | |
| C 11H 22NO 7PS | |
| Molar mass | 343.333641 | 
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references | |
Coenzyme B is a coenzyme required for redox reactions in methanogens. The full chemical name of coenzyme B is 7-mercaptoheptanoylthreoninephosphate. The molecule contains a thiol, which is its principal site of reaction.
Coenzyme B reacts with 2-methylthioethanesulfonate (methyl-Coenzyme M, abbreviated CH
3–S–CoM), to release methane in methanogenesis:
- CH
 3–S–CoM + HS–CoB → CH
 4 + 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:
- HS–CoM + HS–CoB +  −O
 2CCH=CHCO−
 2 → −O
 2CCH
 2–CH
 2CO−
 2 + CoB–S–S–CoM