Partial Separation and Some Kinetic studies of Glutathione S-Transferrase (GST) in Human Serum

This study attempts to isolate the GST from serum of human in city center of Mosul. Three proteinous components had been isolated by gel filtration chromatography from the precipitate produced by ammonium sulfate. It was found that only the second peak had a high activity for GST. The apparent molecular weight of the isolated GST using gel filtration chromatography and SDS-PAGE was(24,717) and (24,807) dalton respectively.
Maximum activity for GST was obtained using (22.463) mmol/l of 1-chloro-2,4-dinitrobenzene (CDNB) as substrate, phosphate buffer (0.11 M/l) as a buffer at pH (6.4) for (12) minutes in incubation at (25)C. Using lineweaverburk plot, the maximum velocity (Vmax) and Michaelis constant (Km) were (0.625) mol/ min and (10.526) mmol/l respectively. Benzyl chloride inhibition on the GST activity were investigated and showed noncompetitive inhibition at a concentration of (30) mmol/l.