Purification of glucose 6-phosphate dehydrogenase from goose erythrocytes and kinetic properties

Glucose 6-phosphate dehydrogenase (G6PD) was purified from goose erythrocytes and some characteristics of the enzyme were investigated. The purification procedure was composed of 3 steps: hemolysate preparation, ammonium sulfate precipitation, and 2', 5'-ADP Sepharose 4B affinity gel chromatography. Thanks to the 3 consecutive procedures, the enzyme, having a specific activity of 36.2 EU/mg protein, was purified for a yield of 68.79% and 3892 folds; to ascertain enzyme purity, SDS-PAGE was performed. Optimal pH, stable pH, optimal temperature, molecular weight, and K-m and V-max values for NADP(+) and glucose 5-phosphate (G6-P) substrates were also determined for the enzyme. In addition, K-i values and inhibition type were determined by means of Lineweaver-Burk graphs obtained for such inhibitors as ATP, ADP and NADPH. These materials inhibited the enzyme in a noncompetitive manner.