Coenzyme B

Coenzyme B
IUPAC name 2-[(7-mercapto-1-oxoheptyl)amino]-3-phosphonooxybutanoic acid
Identifiers
CAS number	104302-77-4
PubChem	350
ChemSpider	343 Y
Jmol-3D images	Image 1 Image 2
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
InChI 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
Properties
Molecular formula	C11H22NO7PS
Molar mass	343.333641
Y B (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 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.^[1] The molecule contains a thiol, which is its principal site of reaction.

Coenzyme B reacts with 2-methylthioethanesulfonate (methyl-Coenzyme M, 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=CHCO−
2 → ^–O₂CCH₂–CH₂CO−
2 + CoB–S–S–CoM

References

1. ^ 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:10.1073/pnas.83.12.4238. PMC 323707. PMID 3086878. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=323707. 
2. ^ Thauer RK (September 1998). "Biochemistry of methanogenesis: a tribute to Marjory Stephenson. 1998 Marjory Stephenson Prize Lecture". Microbiology 144 (Pt 9): 2377–406. PMID 9782487. http://mic.sgmjournals.org/cgi/pmidlookup?view=long&pmid=9782487. 
3. ^ Heim S, Künkel A, Thauer RK, Hedderich R (April 1998). "Thiol:fumarate reductase (Tfr) from Methanobacterium thermoautotrophicum—identification of the catalytic sites for fumarate reduction and thiol oxidation". Eur. J. Biochem. 253 (1): 292–9. PMID 9578488. http://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0014-2956&date=1998&volume=253&issue=1&spage=292.