Sequence dependence of oxidation of some repeating pentapeptide sequences of elastin with electrolytically generated Mn(III): synthesis, kinetics and mechanistic study

Channegowda, D. and Kempegowda, B. K. and Rangappa, K. S. (2001) Sequence dependence of oxidation of some repeating pentapeptide sequences of elastin with electrolytically generated Mn(III): synthesis, kinetics and mechanistic study. JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, 14 (10). pp. 716-724.

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Official URL: http://dx.doi.org/10.1002/poc.417

Abstract

The repeating sequence of elastin, valylprolylglycylvalylglycine (VPGVG), its permutation pentamer glycylvalylglycylvalylproline (GVGVP), and its more hydrophobic pentamer glycylphenylalanylglycylvalylproline (GFGVP) were synthesized by classical solution-phase methods and characterized. The kinetics of the oxidation of these pentapeptides (PP) by Mn(III) was studied in the presence of sulphate ions in acidic medium at 25 degreesC. The reaction was followed spectrophotometrically at lambda (max) = 500 nm. A first-order dependence of rate on both Mn(III)] and PP] was observed. The rate is independent of concentration of the reduction product, Mn(H) and hydrogen ions. Effects of varying dielectric constant of the medium and addition of anions such as sulphate, chloride and perchlorate were studied. Activation parameters were evaluated using Arrhenius and Eyring plots. The oxidation products were isolated and characterized. A mechanism involving the reaction of PP with Mn(HI) in the rate-limiting step is suggested. An apparent correlation was noted between the rate of oxidation and the hydrophobicity of these sequences where increased hydrophobicity results in an increased rate of oxidation. Further, it was observed that the pentamers with Pro as C-terminus are more susceptible to oxidation than the pentamer with Gly as C-terminus. Copyright (C) 2001 John Wiley & Sons, Ltd.

Item Type: Article
Uncontrolled Keywords: elastin; pentapeptide sequences; oxidation; Mn(IH)
Subjects: Physical Sciences > Chemistry
Divisions: PG Campuses > Manasagangotri, Mysore > Chemistry
Depositing User: Users 12 not found.
Date Deposited: 19 Apr 2013 13:43
Last Modified: 06 Sep 2013 06:02
URI: http://eprints.uni-mysore.ac.in/id/eprint/4745

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