Some Problems Related to Detection of Methionine Sulphoxide in Protein Hydrolysates.

Abstract

Methionine and methionine sulphoxide are completely oxidized to the sulphone stage by H2O2 treatment on filter paper if the pH of the solutions applied is less than 1.4. Above this pH a mixture of methionine sulphoxide and methionine sulphone is obtained. At pH about 60 practically no sulphone is detected. Under the conditions used when protein hydrolysates are prepared by heating with 6 N HC1 under reflux, methionine sulphoxide is partly reduced to methionine.