Studies on glucose-6-phosphate dehydrogenase from the human parasite, Onchocerca volvulus.

Glucose-6-phosphate dehydrogenase (E.C. 1.1.1.49) was partially purified from the extracts of adult Onchocerca volvulus by affinity chromatography on 2'5'ADP-Sepharose-4B. Kinetic studies revealed a typical bell-shaped pH profile with an optimum lying between pH 7.3 and 7.8. The apparent Km for glucose-6-phosphate was 5.66 x 10(-5) M, whereas that for NADP was 2.17 x 10(-6) M. Suramin, a filaricidal drug, inhibited the enzyme competitively with respect to NADP as a substrate: the apparent Ki values were 2.23 x 10(-6) M and 4.21 x 10(-7) M, respectively, for the crude and purified enzyme preparations. Glucose-6-phosphate dehydrogenase therefore, could be one of the targets of suramin in vivo.