Lactate dehydrogenase isozymes: Qualitative and quantitative changes during primate evolution

Qualitative differences in primate lactate dehydrogenase (LDH) were investigated using starch gel electrophoresis. Three types of mutation were observed: (1) variability in LDH-1, reflected in the intermediate bands, occurring at the species level; (2) variation in LDH-5 reflected in the intermediate bands, occurring at the infraorder level; (3) a variation affecting mobility of the intermediate bands only, not that of LDH-1 or LDH-5. This type of variation occurred several times, probably at the genus level. Between Pan and Homo it was ascertained to be an LDH-5 variation. Quantitative differences in the relative amounts of the B and A subunits were studied by determining the density of bands using a Densicord densitometer. In a series of primate erythrocytes, a progressive increase of B/A ratio took place as the evolutionary scale was ascended. Comparison of homologous tissues of Perodicticus potto and Saimiri sciurea revealed that all tissues, with the exception of liver, exhibited an increase in the B/A ratio.This investigation was supported in part by contract AF 29(600)-5587 and NSF grant GB-7426.