Purification and Characterization of Microsomal and Lysosomal β‐Glucuronidase from Rat Liver by Use of Immunoaffinity Chromatography

Rat liver β‐glucuronidase (EC 3.2.1.31), both from microsomal and lysosomal fractions, were pinked about 9500‐fold over the homogenate with high yield using affinity chromatography prepared by coupling purified specific immunoglobulin G against rat preputial gland β‐glucuronidase to Nepharose 2B and isoelectric focusing. The purified enzymes appeared homogeneous on electrophoresis in polyacrylamide gel and had a molecular weight of approximately 310000. In dodecylsulfate polyacrylamide gel electrophoresis, the microsomal β‐glucuronidase showed a single band corresponding to a molecular weight of 79000, while the lysosomal β‐glucuronidase had three distinct bands which consisted of one major and two minor bands corresponding to molecular weight of 79000, 74000, and 70000, respectively. A broad pH activity curve with a single optimum at pH 4.4 was observed in both the microsomal and the lysosomal β‐glucuronidases. Immunological gel diffusion technique with rabbit antiserum against rat liver lysosomal β‐glucuronidase revealed that the both enzymes had the same or quite similar antigenic determinants.