Solubilization and partial purification of kynurenine hydroxylase from mitochondrial outer membrane and its electron donors

Hiroshi Okamoto, Osamu Hayaishi

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

l-Kynurenine-3-hydroxylase was solubilized from the outer membrane fraction of rat liver mitochondria, and the enzyme was partially purified by ammonium sulfate fractionation. The kynurenine hydroxylase was independent of the cytochrome b5 reductase system which was also localized in the outer membrane fraction. β-NADH was found to be effective as an electron donor for the partially purified kynurenine hydroxylase, as was NADPH. Under conditions in which whole mitochondria were used as enzyme sample, β-NADH seemed not to act as electron donor for the kynurenine hydroxylase, presumably because of diversion of the electron flow to the respiratory chain in mitochondrial inner membrane. When the electron transfer in the respiratory chain was inhibited by rotenone, antimycin A, or cyanide, β-NADH became available as electron donor for the kynurenine hydroxylase.

Original languageEnglish
Pages (from-to)603-608
Number of pages6
JournalArchives of Biochemistry and Biophysics
Volume131
Issue number2
DOIs
Publication statusPublished - 1969 May

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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