Mechanism of Oxidation of L‐Histidine by Heptavalent Manganese in Alkaline Medium

Abstract

The kinetics of oxidation of L-histidine by manganese(VII) in aqueous alkaline medium at a constant ionic strength of 0.05 mol dm-3was studied spectrophotometrically. The reaction between permanganate and L-histidine in alkaline medium exhibits 2:1 stoichiometry (KMnO4: L-histidine). The reaction is of first order in [KMnO4], less than unit order in [L-histidine] and [alkali]. Decrease in the dielectric constant of the medium decreases the rate of reaction. Effect of added products and ionic strength of the reaction medium have been investigated. The main products were identified by spot test and I.R. A mechanism involving the free radical has been proposed. In composite equilibrium step L-histidine binds to MnO4-species to form a complex(C). The reaction constants involved in the different steps of mechanism are evaluated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined.

Base-Catalyzed Oxidation of Aminotriazole Derivative by Permanganate Ion in Aqueous Alkaline Medium: A Kinetic Study

“…3 (and the obtained k 1 values) and are also listed in Table 3. The obtained values of K 1 are in a good agreement with those reported in the literature [8,10,17]. The obtained large negative values of S ≠ indicate that there is a decrease in the randomness during the oxidation process.…”

“…Many investigators [8][9][10][11][12][13][14][15][16][17] have suggested that most of the oxidation reactions by permanganate ion in neutral and alkaline media proceed through intermediate complex formation between the oxidant and substrate. Spectroscopic evidence for such a complex was obtained from the UV-Vis spectra, Fig.…”

Silver(I) catalysis of oxidative deamination and decarboxylation of l -asparagine and l -histidine by platinum(IV) in perchloric acid solutions: A comparative kinetics study

“…Q3 19 Amino acids play a significant role in the metabolism and the 20 specific metabolic role of them includes the biosynthesis of 21 polypeptides and proteins, as well as the synthesis of nucleotides 22 [17]. Amino acids oxidation is vital because of its bearing on the 23 mechanism of amino acid metabolism. Kinetics of oxidation of amino 24 acids by various oxidants in different media has been studied earlier 25 by Fawzy et al [5][6][7][8][9]18,26,27] and by other researchers [10][11][12][13][14][15][16][17][19][20][21][22][23][24][25][26] 25], and they often undergo oxidative decarboxylation and 27 deamination.…”

“…L-Histidine (His) is an 34 essential amino acid that finds application as a reducing agent in 35 chemical and biochemical systems. Kinetics of oxidation of L-36 histidine by several oxidants have also been studied previously 37 [8,9,[22][23][24][25][26]. In some of its oxidations, 2-imidazole acetaldehyde was 38 identified to be the main oxidation product.…”

Kinetics And Mechanistic Oxidation Of L-Cysteine Using By –Bromo Pthalimide In Presence Of Chloro – Complex Of Pd (II) As Homogenous Cataylst In Aqueous Aectic Acid Medium

“…Due to such spectacular biological importance and unavoidable necessity, study of amino acid with respect to their various chemical reactions gain huge reputation for researchers.Oxidation of various amino acids has grown its own importance and several remarkable works has been done till date to understand oxidation mechanism of amino acids. Oxidation of various amino acids is well reported by N-halo compounds like, N-boromopthalamide [1][2] , N-bromosuccinimide 3 , benzyltrimethylammonium tribromide 4 , N-Chlorosaccharin 5 , N-iodosuccinimide 6 , and many other oxidants [7][8][9] . There are some most recent references of oxidation of amino acids [10][11][12][13] .…”