Hydrolysis of Glycyrrhetyl Mono-Glucuronide to Glycyrrhetic Acid by Glycyrrhetyl Mono-Glucuronide β-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 β-D-glucuronidase of Eubacterium sp. (species) GLH, has been isolated from human intestinal bacteria. The pattern of GAMG β-D-glucuronidase activity was different from that of GL β-D-glucuronidase activity by Butyl-Toyopearl 650S column chromatography. Thus, these enzymes showed differences in the purification ratio and substrate specificity. After this step, GAMG β-D-glucuronidase was completely separated from GL β-D-glucuronidase by gel filtration through Toyopearl HW-55 S, indicating that the GAMG β-D-glucuronidase is a novel type of β-D-glucuronidase which hydrolyzes one glucuronic acid linkage of GA.