Characterization of two hetero-β-galactosidases from monkey small intestine

Abstract

Two hetero-β-galactosidases have been demonstrated in monkey small intestine and have been differentiated by their cellular location and kinetic properties. The pH optima of the partially purified "particulate" and "supernatant" β-galactosidases were found to be 4.5 and 7.0 respectively. The particulate enzyme also catalyzes the hydrolysis of lactose while the supernatant enzyme has no demonstrable activity toward lactose and this activity is not due to contamination by the major intestinal lactase. Both of the enzymes hydrolyze β-glucosides in addition to a variety of β-galactosides. Heavy metal ions and p-hydroxymercuribenzoate are inhibitory and the inhibition by the latter could be reversed by β-mercaptoethanol. No metal ion requirement could be shown.