Effects of Some Environmental Variables on Urease in Germinating Chickpea (Cicer arietinum L.) Seed
Journal Title: Журнал ÑтреÑÑ-физиологии и биохимии - Year 2013, Vol 9, Issue 3
Abstract
Enzyme activity is influenced by a large number of factors. Environmental conditions such as pH, temperature, salt concentration, substrate concentration, activators, and inhibitors may change the three dimensional shape of an enzyme, altering its rate of activity and/or its ability to bind substrate. The effects of such environmental factors were evaluated. The optimum pH and temperature of the purified urease were 7.2 and 48°C, respectively, using urea as substrate. The optimum substrate (urea) concentration for urease was 25 mM. The enzyme showed the highest activity when incubated for 30 min at 48[sup]0[/sup]C. EDTA, a metal chelator, decreased the enzyme activity significantly. This may be due to the removal of metal ions located on or near the active site. Divalent cations like Ba[sup]2+[/sup] and Mg[sup]2+[/sup] slightly stimulated the enzyme at a concentration of 1-3 mM whereas Na[sup]+[/sup] and K[sup]+[/sup] produced little or no effect on the activity. Ca[sup]2+[/sup] enhanced urease activity by 120.47%, while Pb[sup]2+[/sup], Cu[sup]2+[/sup], Zn[sup]2+[/sup] and Hg[sup]2+[/sup] almost completely inhibited the urease activity.
Authors and Affiliations
M. Shaela Pervin, A. Y. K. Masud Rana, N. Sana, R. Shaha
Keywords
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