Role of tryptophan residues of lipoxygenase-1 in activity, structure and stability: Chemical modification studies with N-bromosuccinimide

Srinivasulu, Sonati and Appu Rao, A. G. (2000) Role of tryptophan residues of lipoxygenase-1 in activity, structure and stability: Chemical modification studies with N-bromosuccinimide. Food Chemistry, 70. pp. 199-204. ISSN 0308-8146

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Abstract

The tryptophan residues of lipoxygenase-1 (LOX1) from soybeans (Glycine max) were modi®ed using N-bromosuccinimide under both native and denaturing conditions. The accessibility of tryptophan residues was pH-dependent. Only one tryptophan residue was accessible at the optimum pH of enzyme activity and with a decrease in pH from 9 to 2, the accessibility increased. Modification of the accessible four tryptophan residues at pH 4.0 under non-denaturing conditions resulted in complete loss of enzyme activity; one tryptophan residue was critical for enzyme activity. Modification of the tryptophan residues did not alter the substrate binding affinity; the presence of the substrate during modification did not alter the extent of modi®cation. Modification of the surface-exposed tryptophans did not affect (i) the conformation or structural integrity but (ii) decreased the stability.

Item Type:	Article
Uncontrolled Keywords:	Lipoxygenase-1; N-Bromosuccinimide; Tryptophan residues; Structure and stability
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:	06 Jun 2005
Last Modified:	28 Dec 2011 09:24
URI:	http://ir.cftri.res.in/id/eprint/8

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