Kinetics of oxidation of amino acids by alkaline hexacyanoferrate(III)

Abstract

The kinetics of the oxidation of α‐amino acids (glutamic acid and aspartic acid) by alkaline hexacyanoferrate(III) were studied at constant ionic strength and over the temperature range 323–348 K. The rate was dependent on the first power of the concentrations of substrate and oxidant, but was independent of the concentration of alkali in the range studied. The value of kH/kD was in the range 8·1–8·3 for the slow step, indicating the loss of a hydrogen atom from the CH bond, giving a radical species which was characterized by ESR spectroscopy. The reaction proceeds by way of the α‐imino acid, formed in a fast step, which undergoes hydrolysis to give the corresponding α‐keto acid.

Mechanism of oxidation of alanine by chloroaurate(III) complexes in acid medium: Kinetics of the rate processes

“…The mechanism of redox reactions involving amino acids is therefore of immense importance. A number of kinetic studies have been reported for the oxidation of some amino acids by different metal ion oxidants such as Fe III 1,2, Ag III 3,4, V V 5,6, Ce IV 7,8, Bi V 9, and Mn VII 10–14 in aqueous acidic or alkaline medium. Over the past few years studies in the chemistry of gold(I) and gold(III) compounds have received much attention.…”

Oxidation and Reduction

“…The reaction proceeded via a radical intermediate. 132 The Ir(III)-catalysed oxidation of l-phenylalanine (Phe) to phenylpyruvic acid was first order in OH − and the order with respect to Phe changed from first order to zero order with increasing Phe concentration. 133 The Os(VIII)-catalysed oxidation of l-cystine was first order in Os(VIII) and OH − and zero order in cysteine; formation of an intermediate complex by OsO 4 (OH) 2 2− and Fe(CN) 6 3− ions has been proposed.…”

Effects of nonionic micellar aggregates on the electron transfer reaction between l‐glutamic acid and gold(III) complexes

“…Metal ions play a significant role in the oxidative decarboxylation of amino acids. A number of kinetic studies have been reported for the oxidation of glutamic acid by different oxidants such as Fe(III) [4,5], Mn(III) [6], Mn(VII) [7,8], 1-chlorobenzotriazole [9], N-bromobenzenesulfonamide [10], and tetra butyl ammonium tribromide [11]. Among the metal ion oxidants, gold(III) compounds draw the special interest due to their biological importance [12][13][14][15][16][17][18].…”