Reduction of Chymotrypsin Aα by Dithiothreitol

Treatment of chymotrypsin Aα with dithiothreitol (10 mM) at pH 9.2 in the presence of 8 M urea results in the complete reduction of the disulfide linkages of the protein. Reduction of a single disulfide bond of the enzyme can be achieved by treatment with 10 mM dithiothreitol at pH 9.2 in the presence of 100 mM hydrocinnamate. No such disulfide cleavage occurs in the case of indoleacryloyl chymotrypsin upon treatment with dithiothreitol.