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Purification and properties of urease from the cyanobacterium Anabaena cylindrica
M E Argall1, G D Smith, N P Stamford
1Division of Biochemistry and Molecular Biology, School of Life Sciences, Faculty of Science, Australian National University, Canberra.
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.