Methods of Glutathione Assay—A Review of Classical Methods

Abstract

This chapter reviews different methods of glutathione assay. Modern research is concerned with the role of glutathione in tissue metabolism. The most popular assay for glutathione is based on the fact that iodine will quantitatively oxidize the sulfhydryl group. The determination of glutathione by iodometric titration can be made more specific if the glutathione is selectively precipitated with cadmium lactate before analysis. Glutathione is a specific activator of the enzyme glyoxalase, which converts methylglyoxal to lactic acid. Under conditions in which glutathione is the limiting factor, the rate of this conversion is determined by the concentration of the glutathione. An amperometric method using iodine has been reported, but it requires the prior removal of ascorbic acid with indophenol dye and is, thus, more complicated. Glutathione on hydrolysis forms cysteine that is required for the growth of certain microorganisms, which may serve as a basis for the assay of glutathione. Glutathione may be determined by paper chromatography in a manner similar to that used for amino acids.