Cyclopropylglyoxylate as a mechanistic probe of thiamine pyrophosphate dependent pyruvate-metabolizing enzymes

David J. Livingston, Spencer L. Shames, Robert Gennis, Christopher T. Walsh

Research output: Contribution to journalArticlepeer-review

Abstract

Four pyruvate-decarboxylating enzymes with thiamine pyrophosphate (TPP) cofactors catalyze the decarboxylation of the cyclopropyl substrate analog cyclopropylglyoxylate. Pyruvate: ferredoxin oxidoreductase, an archaebacterial enzyme which catalyzes oxidation of the hydroxyethyl-TPP (HETPP) intermediate by two one-electron transfers to an iron-sulfur center, generates the coenzyme A thioester of cyclopropylcarboxylic acid. A long-lived free radical, HETPP is thought to be an intermediate in the pyruvate to acetyl-CoA conversion; however, cleavage of the cyclopropyl ring was not detected. Pyruvate decarboxylase, pyruvate oxidase, and pyruvate dehydrogenase also generate the corresponding cyclopropyl products. The applicability of cyclopropyl substrate analogs as indicators of free-radical enzyme mechanisms is discussed in light of these results.

Original languageEnglish (US)
Pages (from-to)358-365
Number of pages8
JournalBioorganic Chemistry
Volume15
Issue number4
DOIs
StatePublished - Dec 1987

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Drug Discovery
  • Organic Chemistry

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