G6PD in Immature and Mature Human Brain

Abstract

The isoenzyme polymorphism and kinetics of glucose-6-phosphate dehydrogenase (G6PD) in embryonal and mature human brain were studied. Two types of electropherograms were found in embryonal brains: type I is characterized by 2 G6PD fractions: slow and fast, and in the type II a single, fast-moving G6PD fraction was seen in a single embryo. The additional studies, i.e., re-electrophoresis following 2-mercaptoethanol and NADP treatment and the specific enzyme kinetics (i.e., altered Km and enhanced utilization of the deamino-NADP analog which are typical of the fast-moving fraction in embryonal brain) favor unequivocally the presence of a new, unknown, phase-specific isoenzyme of G6PD. Its synthesis takes place only during embyronal brain development. A probable autosomal localization for the gene of brain G6PD is suggested.