Partial Purification and Characterization of Two β-Glucuronidases from Alcaligenes NG-11

Abstract

A strain of Alcaligenes isolated from soil was a good producer of β-glucuronidase, and the enzyme was purified from the cell-free extract by sequential column chromatography on DEAE-Toyopearl, Toyopearl HW-55F, and Phenyl-Sepharose CL-4B. By these procedures, two β /3-glucuronidases designated as β-glucuronidases I and II were purified 240- and 508-fold, respectively. δ-Glucuronidase I, with a molecular weight of 75, 000, had an optimum pH at 7.5 and the enzyme II, with a molecular weight of 300, 000, had maximum activity at pH 6.0. Both enzymes were strongly inhibited by saccharo-1, 4-lactone, glucaro-δ-lactam, p-chloromercuribenzoate, Hg²⁺, and N-bromosuccinimide. β-Glucuronidase I was active toward estrogen-3-β-glucuronides and inert toward β-glucuronide conjugates of menthol, estrogen-17β-, estrogen-16α-, androsterone-3α-, testosterone-17β-, cortisol-17α-. β-Glucuronidase II hydrolyzed all of these substrates. β-Glucuronidase I was inhibited by phenolphthalein and its glucuronide.