β-Glucuronidase Isoenzymes of Rat-Liver Lysosomes

β-Glucuronidase (β-D-glucuronide glucuronohydrolase, EC 3.2.1.31) from liver lysosomes of male Sprague–Dawley rats was purified by (NH4)2SO4 precipitation, treatment with trypsin and gel filtration on Sephadex G-200, and then fractionated into five active components by ion-exchange chromatography on DEAE-Sephadex A-25 or DEAE-cellulose. All five isoenzymes were shown to be electrophoretically and ultracentrifugally homogeneous. Their sedimentation coefficients range from 12.27 to 13.39. All five isoenzymes appear to be glycoproteins.