CSIR Central


Field	Value

Title	Ribonuclease Rs from Rhizopus stolonifer: lowering of optimum temperature in the presence of urea

Creator	Deshpande, RA Kumar, AR Khan, MI Shankar, V

Subject	Biochemistry & Molecular Biology; Biophysics

Description	RNase Rs showed an approx. 2-fold increase in its activity when incubated in the presence of 2 M urea at 37 degreesC. The increase in its activity, in the presence of urea, was comparable to the activity at its optimum temperature, i.e. 45 degreesC. Compared to the native enzyme at 37 degreesC, the K-m and V-max of RNase Rs at 45 degreesC and in the presence of 2 M urea at 37 degreesC showed an increase while k(cat)/K-m decreased. Arrhenius plots in the presence and absence of urea showed a decrease in the activation energy in the presence of urea. Though there was no change in the secondary structure of the protein in the presence of urea, minor changes were observed in the tertiary structure. Hence, the increase in the activity of RNase Rs, in the presence of 2 M urea at 37 degreesC, is due to the lowering of the activation energy as a result of changes in the microenvironment of the active site. (C) 2001 Elsevier Science B.V. All rights reserved.

Publisher	ELSEVIER SCIENCE BVAMSTERDAMPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS

Date	2011-09-24T09:15:12Z 2011-09-24T09:15:12Z 2001

Type	Article

Identifier	BIOCHIMICA ET BIOPHYSICA ACTA-PROTEIN STRUCTURE AND MOLECULAR ENZYMOLOGY 0167-4838 http://hdl.handle.net/123456789/24134

Language	English