Oxidation of tryptophan by H2O2 in model systems
1990
Kell, G. | Steinhart, H.
Degradation reactions of tryptophan (trp) and the dipeptides alanytryptophan (ala-trp) and phenylalanyltrytophan (phe-trp), induced by H2O2, were investigated under different conditions in aqueous systems. Decreases in the content of trp as well as the formation of soluble degradation products were determined. Highest losses of trp were obtained after H2O2 treatment at 100 degrees C for 2 hr at pH 8.5. Lowest losses occurred at pH 4.0, 25 degrees C, for 30 min. The destruction of trp in ala-trp was similar, while losses of trp in phe-trp under the same reaction conditions were lower. This was indicative of a negative induction effect of the phenyl ring. The quantity of degradation products showed extensive variations, dependent upon the radical mechanism of the oxidation reaction.
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