American Journal of Chemistry
p-ISSN: 2165-8749 e-ISSN: 2165-8781
2013; 3(2): 30-35
doi:10.5923/j.chemistry.20130302.02
K. B. Sudha Rani1, S. Ananda1, N. M. Made Gowda2
1Department of Studies in Chemistry, University of Mysore, Manasagangothri, Mysore–570 006, India
2Department of Chemistry, Western Illinois University One University Circle, Macomb, IL 61455, USA
Correspondence to: N. M. Made Gowda, Department of Chemistry, Western Illinois University One University Circle, Macomb, IL 61455, USA.
Email: |
Copyright © 2012 Scientific & Academic Publishing. All Rights Reserved.
One of the greatest challenges in oxidation research today is the determination ofin vivo oxidative stresses. In this investigation, the spectrofluorometry is used to monitor the kinetics of chloramine-T (CAT) oxidation of L-tryptophan (Trp) in basic solutions. The Trp-CAT reaction progress has been monitored at λmax = 485 nm (after using the excitation wavelength of 360 nm) over the temperature range, 293-313 K. The redox reaction follows a first-order dependence of the rate each on [CAT] and [Trp], and an inverse fractional-order on [OH-]. Variations of the ionic strength and the solvent dielectric constant have no effect on the rate. An addition of the reduction product of CAT, p-toluenesulfonamide, to the reaction mixture also has no influence on the rate. Based on the temperature effect, activation parameters are evaluated. A mechanism consistent with the observed kinetic and activation data has been proposed and the rate-law derived.
Keywords: Oxidation, Reduction,L-Tryptophan, Chloramine-T, Spectrofluorometry, Mechanism, Rate Law
Cite this paper: K. B. Sudha Rani, S. Ananda, N. M. Made Gowda, Kinetics and Mechanism of L-Tryptophan Oxidation by Chloramine-T in Basic Medium: A Spectrofluorometric Study, American Journal of Chemistry, Vol. 3 No. 2, 2013, pp. 30-35. doi: 10.5923/j.chemistry.20130302.02.
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Figure 1. Representative first-order plot for the oxidation of L-Trp by CAT.[L-Trp]0 = 3.48×10-3 M, [CAT]0 = 2.08×10-2 M, [OH-] = 0.130 M, T = 300K, Excitation λmax = 360 nm, Emission λmax = 485 nm |
Figure 2. Effect of varying concentrations of L-Trp on the reaction rate. [CAT]0 = 2.08×10-2 M, [OH-] = 0.130 M, T = 300K |
Figure 3. Effect of OH- ion concentration on the oxidation of L-Trp.Reaction conditions are as in Table 2 |
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Figure 4. Eyring plot for the oxidation of L-Trp by CAT. Reaction conditions are as in Table 3 |
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Scheme 1. Oxidation of L-Trp by CAT |
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Scheme 2. Electronic scheme for the Trp oxidation by chloramines-T in basic medium |
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