Biosynthesis of the 7-mercaptoheptanoic acid subunit of component B of methanogenic bacteria

Journal Article · Tue Jan 24 00:00:00 EST 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00428a068· OSTI ID:5564765

White, R H ^[1]

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1. Virginia Polytechnic Institute and State Univ., Blacksburg (USA)

Deuterium- and {sup 13}C-labeled precursors were used to establish the pathway for the biosynthesis of the 7-mercaptoheptanoic acid moiety of component B in methanogenic bacteria. The extent and position of the label incorporated into 7-mercaptoheptanoic acid were measured from the molecular and fragment ions in the mass spectrum of the methyl ester methylthiol derivative of the 7-mercaptoheptanoic acid. Deuterium from (2,2,2-{sup 2}H{sub 3})acetate was found to be incorporated into four separate positions of 7-mercaptoheptanoic acid. One deuterium was equally distributed between the C-2 and the C-3 of the 7-mercaptoheptanoic acid, and the remaining three were at carbons 4-6. The extent of incorporation of the C-2 and C-3 positions was the same as that observed for the incorporation of (2,2,2-{sup 2}H{sub 3})acetate into the {alpha}-ketoglutarate produced by the cells. (1,2-{sup 13}C{sub 2})Acetate was incorporated into four separate sites of the 7-mercaptoheptanoic acid molecule. On the basis of this and additional information, it is concluded that 7-mercaptoheptanoic acid is biosynthesized from {alpha}-ketosuberate, which arises from {alpha}-ketoglutarate by repeated {alpha}-keto acid chain elongation. The mechanism for the conversion of {alpha}-ketosuberate to a thiol appears to be analogous to that for the conversion of sulfopyruvate to coenzyme M (2-mercaptoethanesulfonic acid).

• OSTI ID: 5564765
• Journal Information: Biochemistry; (USA), Vol. 28:2; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
COENZYMES
BIOSYNTHESIS
METHANOGENIC BACTERIA
BIOLOGICAL PATHWAYS
ACETATES
ACETIC ACID
CARBON 13
DEUTERIUM COMPOUNDS
HEPTANOIC ACID
MASS SPECTRA
SUCCINIC ACID
THIOLS
BACTERIA
CARBON ISOTOPES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
DICARBOXYLIC ACIDS
EVEN-ODD NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
MONOCARBOXYLIC ACIDS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
SPECTRA
STABLE ISOTOPES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques