Microsomal glutathione transferase: Lipid-derived substrates and lipid dependence

Erifili Mosialou, Fiorella Piemonte, Claes Andersson, Ria M E Vos, Peter J. van Bladeren, Ralf Morgenstern

Research output: Contribution to journalArticle

Abstract

Rat liver microsomal glutathione transferase was found to display glutathione peroxidase activity toward a variety of oxidized lipids. 1-Linoleoyl-2-palmitoyl phosphatidylcholine hydroperoxide, 2-linoleoyl-1-palmitoyl phosphatidylcholine hydroperoxide, 2-linoleoyl-1-palmitoyl phosphatidylethanolamine hydroperoxide, and cholesteryl linoleate hydroperoxide all served as substrates (0.02, 0.04, 0.02, and 0.02 μmol/min mg, respectively). The phospholipid hydroperoxide glutathione peroxidase activity of the enzyme was found not require detergent and increased when liposomes containing peroxidized phospholipid were fused with liposomes containing microsomal glutathione transferase. Methyl linoleate ozonide serves as a very efficient substrate for the microsomal glutathione transferase. The unactivated and N-ethylmaleimide-activated enzyme displayed specific activities of 0.74 and 5.9 μmol/min mg, respectively. Upon examination of a series of 4-hydroxyalk-2-enals it was found that the catalytic efficiency of the enzyme increases from the 4-hydroxyhept-2-enal up to the 4-hydroxytetradec-2-enal. The specific activities with the various 4-hydroxyalk-2-enals tested varied between 0.28 and 0.95 μmol/min mg. The phospholipid dependence of the microsomal glutathione transferase was examined in proteoliposomes formed by cholate dialysis. Phosphatidyl choline, phosphatidyl serine, phosphatidyl ethanolamine, and rat liver microsomal phospholipids could all be used successfully to reconstitute the enzyme. In conclusion, microsomal glutathione transferase can detoxify a number of lipid peroxidation products as well as fatty acid ozonide. The results imply a protective role for the enzyme under conditions of oxidative stress.

Original languageEnglish
Pages (from-to)210-216
Number of pages7
JournalArchives of Biochemistry and Biophysics
Volume320
Issue number2
DOIs
Publication statusPublished - Jul 10 1995

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Keywords

  • glutathione transferase
  • hydroxyalkenal
  • lipid dependence
  • lipid hydroperoxides

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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