Abstract
Glucose-6-phosphate dehydrogenase (E. C. 1. 1. 1. 49) (G6PD) from pig red cell was purified by DEAE-sephadex A-50 chromatography and gel filtration on G-100 and G-25. Ammonium sulfate precipitation was used after the DEAE-Sephadex A-50 and Sephadex G-100 steps. The final enzyme preparation had a specific activity of 18 enzyme units/mg. The determination of apparent Km values for G6P and NADP displayed that the enzyme has greater affinity for NADP than for G6P. Based on high Ki value for NADPH, the pig red cell G6PD appears not to be significantly regulated by NADPH. On the other hand, the enzyme appears to be more susceptible to inorganic phosphate as an inhibitor than NADPH since the Ki value for inorganic phosphate is many-fold less than that for NADPH.
