Microheterogeneity of glucose-6-phosphate dehydrogenase phenotypes.

Glucose-6-phosphate dehydrogenase (G-6-PD) is the first enzyme of the pentose phosphate pathway and has been extensively investigated. Several variants of G-6-PD were encountered in different regions of Saudi Arabia during an extensive screening programme. A modified rapid isoelectric focussing procedure using LKB Ampholine PAG plates (pH 5.5-8.5) was used to separate the isoenzymes of G-6-PD. G-6-PD-B+ (the normal enzyme) was separated into five major and three minor fractions. The pattern obtained for G-6-PD-A+, G-6-PD-A-, G-6-PD-Mediterranean and G-6-PD-Mediterranean-like showed that the variants differ significantly in their isoenzyme pattern. In this paper it is shown that isoelectric focussing is a sensitive, powerful and reproducible technique to study microheterogeneity of red cell enzymes.