title: Purification and properties of urease from the cyanobacterium Anabaena cylindrica.
abstract: A purification procedure has been developed by which urease activity in extracts from the cyanobacterium Anabaena cylindrica was enriched 500-fold. The procedure involves MgSO4 precipitation at 55 degrees C and chromatography on hydroxylapatite and diethylaminoethyl sephadex. Its molecular weight was measured by sedimentation equilibrium in an airfuge to be 197,000 +/- 2000 with an estimated subunit molecular weight of 32,000 as determined by polyacrylamide gel electrophoresis. The pH- and temperature-dependence of the enzyme were determined and the activity found to be optimal at pH 8 and 30 degrees C, respectively. The concentration-dependence of the activation of the enzyme by Mg++ was measured, as were the effects on activity of a range of other metal ions.
authors.affiliation: Division of Biochemistry and Molecular Biology, School of Life Sciences, Faculty of Science, Australian National University, Canberra.
authors.forename: M E
authors.initials: ME
authors.lastname: Argall
authors.forename: G D
authors.initials: GD
authors.lastname: Smith
authors.forename: N P
authors.initials: NP
authors.lastname: Stamford
authors.forename: B N
authors.initials: BN
authors.lastname: Youens
mesh_terms: D017033:Anabaena / Q000201:enzymology*; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000378:metabolism; D008970:Molecular Weight; D013696:Temperature; D014510:Urease / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D014510:Urease; D008274:Magnesium