Kinetics of Oxidative Deamination and Decarboxylation of L-Asparagine by Alkaline Permanganate: a Mechanistic Approach

Abstract

Abstract The kinetics of oxidative deamination and decarboxylation of L-asparagine (L-Aspg) by aqueous alkaline permanganate at constant ionic strength of 0.50 mol dm-3 were studied spectrophotometrically. The reaction exhibits first-order kinetics in [permanganate ion] and fractional-order dependences in [L-Aspg] and [alkali]. Initially added products such as aldehyde, ammonia and manganate have no significant effect on the rate of reaction. An increase in ionic strength and a decrease in dielectric constant of the medium increase the rate. The oxidation process in alkaline medium has shown to proceed via two paths: One a substrate dependent path, the other a substrate independent path. The constants involved in the mechanism were evaluated. There is a good agreement between observed and calculated rate constants. The activation paramaters with respect to slow step of path I and path II were calculated.