Purification and properties of the mediterranean fruit fly Ceratitis capitata W. glutathione S-transferase

A. Yawetz*, B. Koren

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Glutathione S-transferase from the mediterranean fruit fly Ceratitis capitata was purified to apparent homogeneity. The enzyme has an iso-electric point near pH 5.7, and a molecular weight of 43,000. The protein is composed of two, almost identical subunits of 22,000 and 21,000 molecular weight. The purified enzyme catalyzed bisubstrate reaction involving 1-chloro-2,4-dinitrobenzene and reduced glutathione followed a steady-state random mechanism. The inhibitory effect of the S-substituted reduced glutathione derivative, S-(4,6-dinitrophenyl)glutathione on the conjugation of 1-chloro-2,4-dinitrobenzene displayed noncompetitive inhibition pattern. The organophosphorus insecticide malathion was a competitive inhibitor of 1-chloro-2,4-dinitrobenzene conjugation. An Arrhenius plot for the conjugation of 1-chloro-2,4-dinitrobenzene yielded a straight regression line with no apparent temperature breaks being evident. The same enzyme catalyzed the conjugation of reduced glutathione with methyl iodide, styrene oxide, and parathion.

Original languageEnglish
Pages (from-to)663-670
Number of pages8
JournalInsect Biochemistry
Volume14
Issue number6
DOIs
StatePublished - 1984

Keywords

  • 1-chloro-2
  • 4-dinitrobenzene
  • Ceratitis capitata
  • conjugation
  • glutathione S-transferase
  • inhibition
  • kinetics
  • methyl iodide
  • parathion
  • purification
  • styrene oxide

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