Acetic anhydride: an intermediate analogue in the acyl-exchange reaction of citramalate lyase

Eur J Biochem. 1976 Apr 15;64(1):263-7. doi: 10.1111/j.1432-1033.1976.tb10296.x.

Abstract

1. Reactivation of deacetyl citramalate lyase by acetic anhydride proceeds through an enzyme-anhydride complex prior to actual acetylation. The reaction is inhibited by citramalate which is competitive with acetic anhydride. 2. A corresponding complex is an intermediate in the carboxymethylation of deacetyl enzyme by iodoacetate. However, the inhibition of this reaction by S-citramalate appears to be non-competitive with iodoacetate. 3. The results lead to the conclusion that acetic anhydride can be regarded as a structural analogue of citramalic acetic anhydride, the proposed intermediate in the acyl exchange reaction on citramalate lyase. 4. The formation of 6-citryl thiolester from the 1-thiolester via the cyclic citric anhydride provides a chemicla model for enzymic acyl exchange. 5. The data suggest that anhydrides are of general importance in acyl exchange reactions of thiolesters.

MeSH terms

  • Acetates / pharmacology
  • Anhydrides / pharmacology
  • Binding Sites
  • Clostridium / enzymology
  • Iodoacetates / pharmacology
  • Kinetics
  • Oxo-Acid-Lyases / metabolism*
  • Protein Binding

Substances

  • Acetates
  • Anhydrides
  • Iodoacetates
  • Oxo-Acid-Lyases