... theaverage of three independent measurements ± SD.Proteinase K activity assayProteinase K activity was determined at 25 °CwithN-succinyl-Ala-Ala-Ala-p-nitroanilide as substrate [26].Assay mixtures ... Kiefhaber, T. & Baldwin, R.L. (1996) Hydrogen exchange andthe unfolding pathway of ribonuclease A. Biophys. Chem. 59,351–356.36.Navon ,A. ,Ittah,V.,Laity,J.H.,Scheraga,H .A. ,Haas,E.&Gussakovsky, ... in the changes of thetertiary and secondary structures are reflected in the activity of RNase A, its activity towards cCMP was measured as a function of the concentration of trifluoroethanol (Fig....