Autosomal genetic control of the activity of an esterase in rat hepatic microsomes

Differences in the electrophoretic pattern of hepatic microsomal esterases have been observed in the outbred Sprague-Dawley strain of albino rats. Two distinct phenotypes occurred which were characterized by either the presence or the near absence of one major band and one minor band of esterase activity in disc gel electrophoretograms. Matings between different combinations of the two phenotypes indicated that the presence of these esterase bands is under the control of an autosomal dominant gene. The estimation of α-naphthylacetate hydrolysis on the gels showed that animals with the extra bands have higher activities than those without them and that essentially all of the higher total activity could be accounted for by the presence of the two extra bands. However, animals with these bands were found to have lower esterase activity in assays utilizing indophenylacetate in vitro.