A comparative study of the conformational stabilities of trypsin and -chymotrypsin

A comparative study was performed on the conformational stabilities of trypsin and α-chymotrypsin. At 45oC, trypsin was most stable at pH 3, while the highest stability of αchymotrypsin was observed at pH 5. With both ester and amide substrates, trypsin displayed activation at pH 3. In the case of α-chymotrypsin, activation was detected at pH 5 only with the amide substrate. The time curves of heat inactivation were complex. For both enzymes, autolysis proceeded with the highest velocity at pH 8. The results obtained on α-chymotrypsin suggested consecutive reactions: the first step, heat denaturation of the protein, is followed by digestion of the damaged molecules. Acta Biol Szeged 45(1-4):43-49 (2001)