Thioredoxin reduction dependent on alpha-ketoacid oxidation by alpha-ketoacid dehydrogenase complexes

FEBS Lett. 1993 Dec 27;336(2):197-200. doi: 10.1016/0014-5793(93)80801-z.

Abstract

The pyruvate and alpha-ketoglutarate dehydrogenase complexes isolated from pig heart mitochondria promote the reduction of thioredoxin in the presence of their alpha-ketoacid substrates, coenzyme A, and free lipoate. Substrate-specific generation of reduced thioredoxin was established by two independent methods, viz. reduction of insulin and thioredoxin reductase-catalyzed NADPH formation. Dihydrolipoate accumulating in the absence of NAD+ is the likely intermediate. A redox function in alpha-ketoacid oxidation provides a potential role for the specific thioredoxins previously identified by us in mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)
  • Animals
  • Catalysis
  • Insulin / chemistry
  • Keto Acids / chemistry*
  • Ketone Oxidoreductases / chemistry*
  • Mitochondria, Heart / enzymology
  • Multienzyme Complexes / chemistry*
  • NADP / chemistry
  • Oxidation-Reduction
  • Pyruvates / chemistry
  • Pyruvic Acid
  • Substrate Specificity
  • Swine
  • Thioredoxin-Disulfide Reductase / chemistry
  • Thioredoxins / chemistry*

Substances

  • Insulin
  • Keto Acids
  • Multienzyme Complexes
  • Pyruvates
  • Thioredoxins
  • NADP
  • Pyruvic Acid
  • Ketone Oxidoreductases
  • 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)
  • Thioredoxin-Disulfide Reductase