Kinetic and Inhibition Studies for Glutathione Peroxidase(GPx) Isolated from Pea (Pisum sativum) Locality

Abstract

This research is included the isolation of glutathione peroxidase(GPx) from the
pea (Pisum sativum), studied the factors effecting the activity of the enzyme and
determination of its molecular weight. One proteinous band had been isolated by gel
filtration sephadex (G-50) from the proteinous supernatant produced by ammonium
sulfate saturation(65%) after dialysis and the product from (G-50) give two bands by
sephadex (G-100). It was found that the first peak (Peak A) had a high activity for
(GPx). The apparent molecular weight of the isolated enzymes using gel filtration
chromatography was (89388+ 850) Dalton for GPx .
The results also showed that the optimum conditions of GPx was obtained at
(100μg/ml) of enzyme concentration using (25 mmol/l) of glutathione(GSH) as a
substrate, phosphate buffer (0.5 mol/l) as a buffer at pH (7.5) for (12) minutes at
(40C). Using Lineweaver–Burk plot, the values of maximum velocity (Vmax) and
Michaelis constant (Km) were (2.1 μmol/ min) and (1.25 mmol/l) respectively. Beside
of, the study showed inhibition for antibiotics, analgesic and other types drugs on the
enzyme activity, especially of psedeuphidrine and flagyl.