| 摘要 |
NEW MATERIAL:A hydrolase diglucuronidase producing diglucuronic acid having the following properties; Molecular weight; 150,000. Isoelectric point; about 5.7 Stable pH; 4-7 (inactivated at 10.0pH). Stable temperature; About <=47 deg. (at 5.0pH for 0.5hr) (inactivated at >=about 58 deg.C). Activity; Capable of producing glycyrrhetinic acid on reacting with glycyrrhizin without producing glucuronic acid. Causing no hydrolysis on reacting with p-nitrophenyl-beta-D-glucuronide which is a substrate of beta-glucuronidase. USE:The hydrolase is reacted with a glycoside having diglucuronic acid as a saccharide component to hydrolyze only the linking part of aglycone moiety to the diglucuronic acid moiety and produce the diglucuronic acid. PREPARATION:Aspergillus niger is cultivated in a culture medium containing an organic carbon source and an organic nitrogen source, and the microbial cell is directly centrifuged to give the aimed hydrolase, which is if necessory purified. |
