Activation of the branched-chain α-ketoacid dehydrogenase complex by a broad specificity protein phosphatase

Robert A. Harris, Ralph Paxton, Rex A. Parker

Research output: Contribution to journalArticle

33 Scopus citations


A broad-specificity protein phosphatase, purified from rat liver, can be used to activate the phosphorylated (inactive) branched-chain α-ketoacid dehydrogenase complex of crude tissue extracts. This enables estimation of the proportion of active (unphosphorylated) complex in a given tissue under different physiological states. Practically all (95 percent) of the complex was found in the active form in rat hearts perfused with leucine as the only oxidizable substrate. In contrast, only 13 percent of the complex was found in the active form when the perfusion medium was supplemented with glucose plus insulin. These findings are consistent with previously measured flux rates through the complex in perfused rat hearts.

Original languageEnglish (US)
Pages (from-to)1497-1503
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number4
StatePublished - Aug 31 1982


ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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