alpha-Tocopherol inhibits human glutathione S-transferase pi.

R.I.M. van Haaften, C.T.A. Evelo, G.R.M.M. Haenen, A. Bast

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Abstract

: Biochem Biophys Res Commun 2001 Jan 26;280(3):631-3 Related Articles, Books, LinkOut


alpha-Tocopherol inhibits human glutathione S-transferase pi.

van Haaften RI, Evelo CT, Haenen GR, Bast A.

Department of Pharmacology and Toxicology, Faculty of Medicine, Universiteit Maastricht, 6200 MD Maastricht, The Netherlands.

alpha-Tocopherol is the most important fat-soluble, chain-breaking antioxidant. It is known that interplay between different protective mechanisms occurs. GSTs can catalyze glutathione conjugation with various electrophiles, many of which are toxic. We studied the influence of alpha-tocopherol on the activity of the cytosolic pi isoform of GST. alpha-Tocopherol inhibits glutathione S-transferase pi in a concentration-dependent manner, with an IC(50)-value of 0.5 microM. At alpha-tocopherol additions above 3 microM there was no GST pi activity left. alpha-Tocopherol lowered the V(max) values, but did not affect the K(m) for either CDNB or GSH. This indicates that the GST pi enzyme is noncompetitively inhibited by alpha-tocopherol. An inhibition of GST pi by alpha-tocopherol may have far-reaching implications for the application of vitamin E. Copyright 2001 Academic Press.
Original languageEnglish
Pages (from-to)631-633
Number of pages3
JournalBiochemical and Biophysical Research Communications
Volume280
DOIs
Publication statusPublished - 1 Jan 2001

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