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Updated: May 24, 2026
Spectrophotometric Screening for Potential Inhibitors of Cytosolic Glutathione S-Transferases
Published on: October 10, 2020
Spectrophotometric assay for serum glutathione transferase: a re-examination
Raffaele Fabrini1, Alessio Bocedi, Renato Massoud
1Department of Chemical Sciences and Technologies, University of Rome Tor Vergata, I-00133, Rome, Italy.
Objectives:
The aim of the present paper is a careful re-examination of an automated spectrophotometric procedure for glutathione transferase (GST) activity in human serum described previously and used in many laboratories.
Design And Methods:
GST activity in human serum has been assayed spectrophotometrically under various experimental conditions. Recombinant human GSTs and specific inhibitors were also used to check the possible occurrence of artifacts.
Results:
Basal level of the enzyme calculated using this method turns out to be much higher than that found using RIA and ELISA procedures. Relevant pH-dependent artifacts deeply affect this spectrophotometric assay. Notably, spectral changes previously interpreted as a measure of basal activity, are mainly due to an increase of the spontaneous reaction between the two substrates.
Conclusion:
GST activity in normal serum cannot be correctly determined with the spectrophotometric assay described previously because of the very low enzyme concentration and the pH-dependent artifacts.
