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A kinetic study of the bisulphite reduction of methionine sulphoxide to methionine
Author(s) -
Snow John T.,
Finley John W.,
Kohler George O.
Publication year - 1976
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740270710
Subject(s) - methionine , chemistry , protonation , kinetics , aqueous solution , ion , bisulfite , ionic strength , inorganic chemistry , organic chemistry , biochemistry , amino acid , quantum mechanics , dna methylation , gene , physics , gene expression
The rates of reduction of methionine sulphoxide to methionine by aqueous bisulphite solutions were measured by n.m.r. spectroscopy. The reaction was shown to follow overall second‐order kinetics, being first‐order with respect to methionine sulphoxide and first‐order with respect to bisulphite anion. The reduction was shown to have a strong pH dependence, reaching a maximum rate at pH 2.9. The pH‐rate profile has been related to the concentrations of bisulphite anion and protonated methionine sulphoxide and to the ionic state of methionine sulphoxide. A mechanism consistent with these results is proposed. An energy of activation of 14.1 kcal/mole was obtained for the reaction. These reductions are proposed to have important nutritional implications.