Effect of N-bromosuccinimide-modification of tyrosine side chains of cardiotoxin II of the Indian cobra on biological activity

Shashidharan, P. ; Ramachandran, L. K. (1987) Effect of N-bromosuccinimide-modification of tyrosine side chains of cardiotoxin II of the Indian cobra on biological activity Journal of Biosciences, 11 (1-4). pp. 287-297. ISSN 0250-5991

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Official URL: http://www.ias.ac.in/jarch/jbiosci/11/287-297.pdf

Related URL: http://dx.doi.org/10.1007/BF02704679

Abstract

The essential role of tyrosine residue(s) of cardiotoxin II in the biological activity of the toxin was evaluated using N-bromosuccinimide. N-bromosuccinimide effected oxidation of the tyrosine residues in cardiotoxin II with enhancement in absorbance at 260 nm. The influence of various solvent media such as acetate-formate buffer (pH 4.0), 0.01 N H2SO4 (pH 2.0) and Tris-HCl buffer (pH 8.5) on oxidation of tyrosine residues was exa mined. In comparison with 0.01 N H2S O4, acetate-formate buffer could prevent secondary oxidations as revealed by lower consumption of oxidant, N-bromosuccinimide, to achieve oxidation. In Tris-HCl buffer oxidation of tyrosine did not take place effectively. N-iodo-succinimide caused only limited oxidation as evident from minor increase in absorbance at 260 nm. N-chlorosuccinimide was completely ineffective. Oxidation of cardiotoxin II with 3.75 equivalents of N-bromosuccinimide tyrosine residue led to complete loss of lethal activity. However, the derivative retained the ability to protect bacterial protoplasts from lysis in solutions of low tonicity. Unlike cardiotoxin II oxidized with N-chlorosuccinimide (50 equivalents/mol of toxin) which retained lethal activity as well as the ability to protect protoplasts from lysis, performic acid-oxidized toxin had lost both the activities.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Cardiotoxin II; Naja naja; N-Bromosuccinimide Oxidation; Essential Tyrosine; Protoplast Stabilization
ID Code:52344
Deposited On:03 Aug 2011 14:24
Last Modified:18 May 2016 05:55

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