Variations in the Lactic Dehydrogenase of Vertebrate Erythrocytes

Erythrocytes from representatives of the 5 classes of vertebrates revealed a marked species variation in the number of LDH isozymes, in the distribution of the total LDH activity among these isozymes, and in their electrophoretic mobilities. Starch gel electrophoresis of hemolysates followed by direct histochemical demonstration of LDH activity with nitro blue tetrazolium as dye and phenazine methosulfate as electron transporter showed that closely related species exhibited similar LDH patterns. The rhesus monkey had LDH isozymes of similar pattern to those of human hemolysate but slightly slower in electrophoretic mobility. The goat and sheep each had 1 band of LDH activity in their erythrocytes of identical electrophoretic mobility, whereas the single band in steer hemolysate migrated slightly faster. The 5 bands of chicken hemolysate were quite similar in pattern to the 5 bands of duck hemolysate but migrated slightly faster and exhibited a different distribution of the total LDH activity. The 2 species of snake each had 1 band of LDH activity with identical mobility. Staining occurred with the levorotatory form of the substrate and not with the dextrorotatory form. Examination of more than 380 human hemolysates failed to reveal any differences among individuals in the main LDH bands. The genetic basis for the species differences in erythrocyte lactic dehydrogenases is discussed.