Branched chain α-ketoacid dehydrogenase and pyruvate dehydrogenase activity in isolated rat pancreatic islets

R. Paxton, R. A. Harris, A. Sener, W. J. Malaisse

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Branched-chain α-ketoacid dehydrogenase and pyruvate dehydrogenase in isolated rat pancreatic islets were shown to be regulated by a phosphorylation/dephosphorylation mechanism. Broad-specificity phosphoprotein phosphatase treatment stimulated and ATP addition inhibited their activities. The kinases responsible for inactivating these complexes were shown to be sensitive to inhibition by known inhibitors, α-chloroisocaproate and dichloroacetate. Total activity (nmol/min/islet @ 37°C) of branched-chain α-ketoacid dehydrogenase and pyruvate dehydrogenase was 0.86 and 5.09, with a % active form (activity before phosphatase treatment divided by activity after phosphatase treatment X 100) of 36% and 94%, respectively. Incubation of intact isolated islets with α-chloroisocaproate affected neither insulin release nor flux through branched-chain α-ketoacid dehydrogenase.

Original languageEnglish (US)
Pages (from-to)317-322
Number of pages6
JournalHormone and Metabolic Research
Volume20
Issue number6
DOIs
StatePublished - 1988

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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