Coenzyme B

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
Names
IUPAC name
2-[(7-mercapto-1-oxoheptyl)amino]-3-phosphonooxybutanoic acid
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
UNII
  • InChI=1S/C11H22NO7PS/c1-8(19-20(16,17)18)10(11(14)15)12-9(13)6-4-2-3-5-7-21/h8,10,21H,2-7H2,1H3,(H,12,13)(H,14,15)(H2,16,17,18) Y
    Key: JBJSVEVEEGOEBZ-UHFFFAOYSA-N Y
  • InChI=1/C11H22NO7PS/c1-8(19-20(16,17)18)10(11(14)15)12-9(13)6-4-2-3-5-7-21/h8,10,21H,2-7H2,1H3,(H,12,13)(H,14,15)(H2,16,17,18)/t8-,10-/m1/s1
    Key: JBJSVEVEEGOEBZ-PSASIEDQBT
  • InChI=1/C11H22NO7PS/c1-8(19-20(16,17)18)10(11(14)15)12-9(13)6-4-2-3-5-7-21/h8,10,21H,2-7H2,1H3,(H,12,13)(H,14,15)(H2,16,17,18)
    Key: JBJSVEVEEGOEBZ-UHFFFAOYAG
SMILES
  • O=C(N[C@@H](C(=O)O)[C@H](OP(=O)(O)O)C)CCCCCCS
  • O=C(NC(C(=O)O)C(OP(=O)(O)O)C)CCCCCCS
Properties
C
11
H
22
NO
7
PS
Molar mass 343.333641
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

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