Separation and properties of β-galactosidase, β-glucosidase, β-glucuronidase and N-acetyl-β-glucosaminidase from rat kidney

Abstract

The activities of [beta]-galactosidase, [beta]-glucosidase, [beta]-glucuronidase and N-acetyl-[beta]-glucosaminidase from rat kidney have been compared when 4-methylumbelliferyl glycosides are used as substrates. Separation by gel electrophoresis at pH 7.0 indicated slow- and fast-moving components of rat-kidney [beta]-galactosidase. The fast-moving component is also associated with the total [beta]-glucosidase activity and inhibition experiments indicate that a single enzyme species is responsible for both activities. DEAE-cellulose chromatography and fntration on Sephadex gels suggests that the [beta]-glucosidase component is a small acidic molecule, of molecular weight approx. 40,000-50,000, with optimum pH 5.5-6.0 for [beta]-galactosidase and [beta]-glucosidase activities. The major [beta]-galactosidase component has low electrophoretic mobility, a calculated molecular weight of 80,000 and optimum pH 3.7.