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Updated: Jul 19, 2026

Spectrophotometric Screening for Potential Inhibitors of Cytosolic Glutathione S-Transferases
Published on: October 10, 2020
Tocopherol esters inhibit human glutathione S-transferase omega
Adriana Sampayo-Reyes1, Robert A Zakharyan
1División de Farmacología y Toxicología, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey Nuevo León, Mexico. adriana.sampayo@biomedicas.net
Abstract:
Human glutathione S-transferase omega 1-1 (hGSTO1-1) is a newly identified member of the glutathione S-transferase (GST) family of genes, which also contains alpha, mu, pi, sigma, theta, and zeta members. hGSTO1-1 catalyzes the reduction of arsenate, monomethylarsenate (MMA(V)), and dimethylarsenate (DMA(V)) and exhibits thioltransferase and dehydroascorbate reductase activities. Recent evidence has show that cytokine release inhibitory drugs, which specifically inhibit interleukin-1b (IL-1b), directly target hGSTO1-1. We found that (+)-alpha-tocopherol phosphate and (+)-alpha-tocopherol succinate inhibit hGSTO1-1 in a concentration-dependent manner with IC50 values of 2 microM and 4 microM, respectively. A Lineweaver-Burk plot demonstrated the uncompetitive nature of this inhibition. The molecular mechanism behind the inhibition of hGSTO1-1 by alpha-tocopherol esters (vitamin E) is important for understanding neurodegenerative diseases, which are also influenced by vitamin E.
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