Abstract
With α-naphthyl butyrate and α-naphthyl acetate as substrates nonspecific esterase activity was demonstrated in both the crypt epithelium and epithelium covering the villus of the small intestine of the rat. This distribution of enzymatic activity does not correspond to the distribution of the so-called "absorptive epithelium." Starch gel electrophoretic analysis of intestinal homogenates showed a spectrum of enzymatically active fractions which hydrolyzed both substrates. The number of enzymic fractions and their electrophoretic mobilities were the same with both substrates, but the butyrate ester was hydrolyzed 2.5 times more rapidly than the acetate ester. These observations are discussed in relation to the rapid differentiation which occurs as cells migrate from the intestinal crypts onto the surface of the villus.