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Role of disulfide bridges in structure-activity relationship of plant lipases from wheat germ and rice bran.

Gopalakrishna, K. N. and Kaul, P. and Kumar, P. R. and Prakash, V. (2002) Role of disulfide bridges in structure-activity relationship of plant lipases from wheat germ and rice bran. Indian Journal of Biotechnology, 1 (2). 188-196, 34 ref..

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Abstract

Disulphide bonds of wheat germ lipase (WGL) and rice bran lipase (RBL) were reduced with sodium borohydride (NaBH4) and DTT under non-denaturing conditions to compare the activity, conformation and stability of reduced forms with those of native enzymes, as judged by kinetics, far UV-CD, fluorescence and thermal denaturation studies as well as microcalorimetric measurements. Activity of the reduced lipases decreased in a sequential manner involving at least 2 steps in both the lipases. The CD spectrum in the far UV-region indicated that overall conformation was markedly affected upon reduction. A decrease in tryptophan fluorescence was observed without any shift in the emission max. The apparent thermal denaturation temp. of reduced WGL and RBL were decreased by 6 and 12C, respectively, compared to the native enzyme. Reduction and carboxymethylation of all 4 cysteines caused extensive unfolding of the enzymes resulting in the loss of activity, conformation and thermal stability, indicating that the disulphide bonds have a major role in stabilizing the native conformation and stability of these 2 lipases.

Item Type: Article
Uncontrolled Keywords: BRAN-; GERM-; LIPASES-; REDUCTION-; RICE-; STABILITY-; WHEAT-; CONFORMATION-; DISULPHIDES-; RICE-BRAN; WHEAT-GERM
Subjects: 600 Technology > 08 Food technology > 21 Cereals
500 Natural Sciences and Mathematics > 07 Life Sciences > 03 Biochemistry & Molecular Biology > 07 Enzyme Biochemistry
Divisions: Protein Chemistry and Technology
Depositing User: Somashekar K.S
Date Deposited: 18 Jul 2011 04:52
Last Modified: 18 Jul 2011 04:52
URI: http://ir.cftri.com/id/eprint/7597

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