Changes in the sub-types of soluble alanine aminotransferase in the liver of rats during development and aging

DEAE-cellulose column chromatography and polyacrylamide gel electrophoresis of crystalline soluble alanine aminotransferase of the liver shows only a single molecular species in both immature and senescent rats. In the case of adult rat, there are two species; one corresponding to that of the immature and the other to that of the old. The former sub-type of the isozyme is designated as sAAT-A and the latter as sAAT-B. sAAT-A is predominantly present in the immature rat and sAAT-B in the old. There is thus a gradual and sequential change in the two sub-types of sAAT as a function of age of the rat.