Studies on the nature of the multiple forms of the glutathione S-transferases.

various concentrations as a selective inhibitor and have found that ATP at a concentration of lOmM abolishes arylsulphatase B activity but only inhibits 50% of the arylsulphatase A activity. By measuring the total activity and the activity in the presence of 1OmM-ATP we have been able to determine the activity of both forms in defined mixtures of the two. Thus the proportions of the two enzymes in crude preparations may be measured without prior separation and, if this property is shared by the human arylsulphatases, could be used clinically as a quick routine test of the separate activities of arylsulphatases A and B.