α,β-Dihydroxyisovalerate dehydratase. A superoxide-sensitive enzyme

C. F. Kuo, T. Mashino, I. Fridovich

研究成果: Article

185 被引用数 (Scopus)

抄録

Increasing the intracellular flux of O2- by incubating aerobic Escherichia coli with paraquat or plumbagin markedly lowered the α,β-dihydroxyisovalerate dehydratase activity detectable in extracts from these cells. This effect was not seen in the absence of dioxygen and was exacerbated by inhibiting protein biosynthesis with chloramphenicol. These effects of paraquat and of plumbagin were both time- and concentration-dependent. Transfer of E. coli from aerobic to anaerobic conditions caused a rebound of the dehydratase activity, in the continued presence of paraquat and of chloramphenicol, indicating the presence of a mechanism for reactivating this enzyme. The instability of the dehydratase activity in cell extracts was exacerbated by selective removal of superoxide dismutase, but not of catalase, by immunoprecipitation. Addition of exogenous superoxide dismutase reversed the effect of immunoprecipitation; whereas catalase or inactive superoxide dismutase were ineffective. We conclude that the dehydratase is inactivated by O2-. This could account for the bacteriostatic effects of dioxygen and of paraquat.

本文言語English
ページ(範囲)4724-4727
ページ数4
ジャーナルJournal of Biological Chemistry
262
10
出版ステータスPublished - 1987 1 1
外部発表はい

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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