Article

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

Mária L. Simon*, Kinga László, Márta Kotormán, Béla Szajáni

Department of Biochemistry, University of Szeged, Szeged, Hungary

A comparative study was performed on the conformational stabilities of trypsin and a-chymotrypsin. At 45ºC, trypsin was most stable at pH 3, while the highest stability of a -chymotrypsin was observed at pH 5. With both ester and amide substrates, trypsin displayed activation at pH 3. In the case of a -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 a -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) PDF

Key Words: trypsin, a-chymotrypsin, conformational stability, autolysis, pH effect

*Corresponding author. E-mail: simon@biocom.bio.u-szeged.hu