[Attempt at characterization of 2 erythrocyte variants of glucose-6-phosphate dehydrogenase in a patient with a partial enzymatic deficit].

The electrophoresis shows, in red blood cells of a North African man affected by a glucose-6-phosphate dehydrogenase deficiency, the presence of two enzymes differing by their electrophoretic mobilities: one of them presents in the same mobility as variant Gd (+) B, the other being faster. After partial purification of the enzymes by ionic exchange chromatography on cellex D BIO-RAD, the preparation obtained shows some kinetic abnormalities: an increased value of 2-deoxy-glucose-6-phosphate utilisation and a non linear plot of 1/v versus 1/s, inadequate for Km determination. Assuming that our preparation contains two enzymes differing by their affinities for glucose-6-phosphate, were carried out a study of their Michaelis constants for glucose-6-phosphate by a method based on the densitometric determination of colored spots corresponding to these two variants after electrophoretic separation on cellogel strips. One of these variants is similar to Gd (+) B, the other being characterised by increased values of: electrophoretic mobility (+ 110%), Km for glucose-6-hosphate (194 +/- 38 muM, normal range being 55 to 70 muM), utilisation coefficient of 2-deoxy-glucose-6-phosphate.