Activity of β-galactosidase in homogenates and isolated microvilli fraction of jejunal mucosa from suckling rats

Abstract
[beta]-Galactosidase activity was studied in homogenates and isolated microvilli fraction of jejunal mucosa from 14-day-old suckling rats. o-Nitrophenyl [beta]-D-galactoside served as the substrate. The microvilli fraction contains about one-third of the total activity of the orginal homogenate. The pH optimum of the [beta]-galactosidase was 3.5 in the total homogenate and supernatant fraction, whereas in the microvilli fraction the maximum activity was at pH 5[middot]5. This work gives further support to the view that two [beta]-galactosidases exist in the jejunal mucosa.