title: [Expression, characterization and application of thermostable beta-glucuronidase from Thermotoga maritima].
abstract: The gene of beta-glucuronidase from Thermotoga maritima was cloned into the plasmid pHsh, and expressed in Escherichia coli JM109. The recombinant protein was purified to homogeneity by a simple step, heat treatment. The recombinant enzyme had a molecular mass of 65.9 kD. The optimal activity of beta-glucuronidase was found at pH 5.0 and 80 degrees C. The purified enzyme was stable over a pH range from 5.8 to 8.2 and had a half life of 2 h at 80 degrees C. The kinetic experiments at 80 degrees C with p-nitrophenyl-beta- glucuronide as substrate gave a K(m) and V(max) of 0.18 mmol/L and 312 u per mg of protein. The purified enzyme could transform glycyrrhizin to glycyrrhetinic acid.
authors.affiliation: School of Biotechnology, Jiangnan University, Wuxi 214122, China.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Wang
authors.forename: Jianjun
authors.initials: J
authors.lastname: Pei
authors.forename: Huazhong
authors.initials: H
authors.lastname: Li
authors.forename: Weilan
authors.initials: W
authors.lastname: Shao
mesh_terms: D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D005966:Glucuronidase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D006034:Glycyrrhetinic Acid / Q000378:metabolism; D019695:Glycyrrhizic Acid / Q000378:metabolism; D006358:Hot Temperature; D007700:Kinetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D020124:Thermotoga maritima / Q000201:enzymology* / Q000235:genetics*
chemical_list: D011994:Recombinant Proteins; D019695:Glycyrrhizic Acid; D005966:Glucuronidase; D006034:Glycyrrhetinic Acid