Studies on variant glucose-6-phosphate dehydrogenases: G6PD fort worth

A new variant (G6PD Fort Worth) of glucose-6-phosphate dehydrogenase has been discovered in a young man of English-Irish descent. Although the enzyme deficiency is severe, it is not associated with chronic hemolytic anemia. The variant has normal electrophoretic mobility and normal stability, but altered kinetic characteristics and altered utilization of substrate analogs. A second variant G6PD has been found in a young man of Irish-Scotch descent. It is associated with chronic hemolytic anemia and is very unstable. The requirement of this variant for high concentrations of NADP for stability at 2-4° suggests that it is either identical to G6PD Torrance or closely related to it. Inhibition studies with NADPH and other kinetic studies have been carried out to evaluate the possible in vivo function of these two variants and also that of G6PD Kilgore.