Hydrolysis of glycyrrhetyl mono-glucuronide to glycyrrhetic acid by glycyrrhetyl mono-glucuronide beta-D-glucuronidase of Eubacterium sp. GLH

Abstract

Glycyrrhetyl mono-glucuronide (GAMG) is an intermediate in the hydrolysis of glycyrrhizin (GL) to glycyrrhetic acid (GA). An enzyme responsible for its hydrolysis, characterized as a GAMG beta-D-glucuronidase of Eubacterium sp. (species) GLH, has been isolated from human intestinal bacteria. The pattern of GAMG beta-D-glucuronidase activity was different from that of GL beta-D-glucuronidase activity by Butyl-Toyopearl 650 S column chromatography. Thus, these enzymes showed differences in the purification ratio and substrate specificity. After this step, GAMG beta-D-glucuronidase was completely separated from GL beta-D-glucuronidase by gel filtration through Toyopearl HW-55 S, indicating that the GAMG beta-D-glucuronidase is a novel type of beta-D-glucuronidase which hydrolyzes one glucuronic acid linkage of GA.