Coenzyme B

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Coenzyme B
Coenzyme B (CoB).svg
Identifiers
CAS number 104302-77-4 YesY
PubChem 350
ChemSpider 343 YesY
Jmol-3D images Image 1
Image 2
Properties
Molecular formula C
11
H
22
NO
7
PS
Molar mass 343.333641
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Coenzyme B is a coenzyme required for redox reactions in methanogens. The full chemical name of coenzyme B is 7-mercaptoheptanoylthreoninephosphate.1 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:2

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:3

CH
3
–S–CoM
+ HS–CoB O
2
CCH=CHCO
2
O
2
CCH
2
–CH
2
CO
2
+ CoB–S–S–CoM

References








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