Erythrocyte glucose-6-phosphate dehydrogenase activity assay and affinity for its substrate under "physiological" conditions.

INHIBITION OF HUMAN ERYTHROCYTE GLUCOSE 6-PHOSPHATE DEHYDROGENASE ACTIVITY BY DEHYDROEPIANDROSTERONE AND RELATED STEROIDS.

The inhibitory effects of several steroids on G6PD activity using intact erythrocytes are reported. Incubation of whole blood with dehydroepiandrosterone (DHEA) resulted in 42% and 12% inhibition in the enzyme activity in the presence and absence of oxygen, respectively. Addition of epinephrine and/or aminophylline into the incubation medium caused further enzyme inhibition suggesting a po...

Glucose-6-phosphate dehydrogenase in vitro correlated with in vivo activity and reticulocytosis.

In vitro activity of erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) does not always correlate with in vivo hemolytic manifestations. Many of these non-correlations are reviewed and can now be explained on the basis of altered substrate affinity and/or altered inhibition by intracellular metabolites. These alterations are not detected by standard assay conditions. The influence of a youn...

Inhibition of Human Erythrocyte Glucose 6-Phosphate Dehydrogenase by Cadmium, Nickel and Aluminium

Measurement of erythrocyte glucose-6-phosphate dehydrogenase activity using a centrifugal analyzer.

We describe two improved methods for determination of erythrocyte glucose-6-phosphate dehydrogenase activity. One method is an “enzyme-linked” procedure in which an excess of 6-phosphogluconate dehydrogenase is used to produce two moles of NADPHfor each mole of glucose-6-phosphate oxidized. In the other method 2,3-diphosphoglycerate is used to inhibit the variable contribution of endogenous 6-p...

Malarial parasite hexokinase and hexokinase-dependent glutathione reduction in the Plasmodium falciparum-infected human erythrocyte.

The metabolism of glucose in Plasmodium falciparum-infected human erythrocytes is increased 50- to 100-fold. This is accomplished in part by parasite-directed synthesis of a protozoan hexokinase with unique kinetic, electrophoretic, and heat stability properties. The total hexokinase activity is increased approximately 25-fold over that of control uninfected erythrocytes of the same age from th...