COMPARISON OF KINETIC-PROPERTIES AND EXPRESSION OF GST-PI (GSTP1-1) IN TISSUES OF MEN AND WOMEN

Previous studies from our laboratory have indicated gender-related dif ferences in the expression and properties of glutathione S-transferase s (GSTs) in humans and such differences have been particularly observe d for GST pi (Singhal et al., BBA 1163. 266-272, 1993). Present studie s were therefore designed to quantitate GST pi in the erythrocytes, lu ng, heart, pancreas, colon, muscle, and skin and to compare the kineti c properties of GST pi purified from these tissues of men and women. T he results of these studies showed remarkably higher specific activiti es for GST pi purified from female erythrocytes (69.2 u/mg vs. 44.3 u/ mg), lung (48.0 u/mg vs. 35.0 u/mg), heart (46.3 u/mg vs. 33.3 u/mg), pancreas (40.0 u/mg vs. 32.6 u/mg), colon (44.4 u/mg vs. 28.4 u/mg), a nd skin (41.5 u/mg vs. 33.0 u/mg), as compared to the enzyme purified from males. The specific activity of GST pi obtained from male skeleta l muscle was however higher than that obtained from females. There wer e no significant differences between the Km values for 1-chloro-2,4-di nitrobenzene for the enzyme isolated from male and female tissues. How ever; except for the muscle, the Vmax values for the enzyme from femal e tissues were considerably higher as compared to that obtained from m ale tissues.