Journal of Stress Physiology & Biochemistry, Vol. 9 No. 3 2013, pp. 345-356 ISSN 1997-0838
Original Text Copyright (cc) 2013 by  Shaela Pervin, Sarowar Jahan, Masud Rana, Sana, Habibur Rahman, Shaha 


ORIGINAL ARTICLE
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Effects of Some Environmental Variables on Urease in Germinating Chickpea (Cicer arietinum L.) Seed

M. Shaela Pervin1, M.G. Sarowar Jahan1*, A.Y.K.Md. Masud Rana2, N.K. Sana1, M. Habibur Rahman1, R.K. Shaha1 

1 Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi-6205, Bangladesh.
2 Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Ganakbari, Savar, P.O. Box No. 3787, Dhaka-1000, Bangladesh.


*E-Mail:
sjahan.biochem@ru.ac.bd

Received  April  23,
2013

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 48C, 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 480C. 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 Ba2+ and Mg2+ slightly stimulated the enzyme at a concentration of 1-3 mM whereas Na+ and K+ produced little or no effect on the activity. Ca2+ enhanced urease activity by 120.47%, while Pb2+, Cu2+, Zn2+ and Hg2+ almost completely inhibited the urease activity.

Key words:     Chickpea, Cicer arietinum, Environmental variable, Enzyme activity, Urease 

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