Effect of urea at lower concentration on the structure of papain - Formation of a stable molten globule and its characterization.

Satish, H. A. and Ramesh Kumar, P. and Prakash, V. (2002) Effect of urea at lower concentration on the structure of papain - Formation of a stable molten globule and its characterization. Indian Journal of Biochemistry and Biophysics, 39. pp. 155-162. ISSN 0301-1208

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Abstract

Effect of lower concentrations of urea on papain was monitored by optical spectroscopy, calorimetry and partial specific volume measurements. At lower concentrations of urea, papain exhibits a different structure and showed an increase in the intensity of circular dichroic (CD) spectra as compared to the native molecule. At lower concentrations (0.2-1.5 M) of urea, binding of 8-anilino-naphthalene sulfonic acid (ANS) to the papain molecule was higher: at 0.5 M, there was about 50% increase in ANS binding. Both calorimetric and spectroscopic studies indicated an increased thennal stability of the molecule at lower concentrations. At 0.5 M urea concentration, the apparent thermal denaturation temperature increased from a control value of 83 ± 1° C to 86 ± 1° C. At isopotential conditions, the partial specific volume of papain was found to be higher in presence of lower concentrations of urea, than the native protein or unfolded molecule. The preferential interaction parameter (Od0g2h.~1.1'-1 showed a negative value in the presence of lower concentrations of urea (0.2-2 M), which was maximum at I M urea with a value of -0.019 g/g. Above 3 M urea, the preferential interaction parameter was positive.

Item Type:	Article
Uncontrolled Keywords:	lower concentrations, urea, papain, molten globule
Subjects:	500 Natural Sciences and Mathematics > 04 Chemistry and Allied Sciences > 29 Protein Chemistry
Divisions:	Protein Chemistry and Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	15 Feb 2018 09:17
Last Modified:	15 Feb 2018 09:17
URI:	http://ir.cftri.res.in/id/eprint/13425

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