Acceptor and Substrate Specificity of β-Glucuronidase with Transglycosylation Activity from Aspergillus niger

Abstract

β-Glucuronidase from Aspergillus niger, which showed transglycosylation activity, was purified from a commercial enzyme preparation. Upon addition of the previously reported acceptors such as D-glucose, the enzyme transferred the glucuronyl residues to 2-deoxy-, 3-deoxy-D-glucose, 2-deoxy-D-galactose, D-galactosamine and D-glucosamine. D-Allose, D-gulose and D-mannosamine were not good acceptors. The enzyme produced three products with D-glucose by transglycosylation, and the structure of the main product was β-D-glucosyluronic acid-(1→4)-D-glucose. Furthermore β-D-glucosyluronic acid-(1→2)-D-glucuronic acid and β-D-glucosyluronic acid-(1→4)-D-glucose were hydrolyzed by the enzyme. The enzyme did not degrade methyl β-glucosiduronic acid or α, β-trehalose dicarboxylate having β-(1→4) glucuronyl linkage.