Table 2.

Measured pK values based on the alanine pentapeptides compared to the pK_int values of Nozaki and Tanford

^aFrom the model compound data in Table 3 of Nozaki and Tanford (1967).

^bThe pK values of the ionizable groups in the alanine pentapeptides used in this work measured in 0.1 M NaCl at 25°C. The errors are the standard deviations from the average of three independent experiments for the α-carboxyl, Glu, α-amino, and Tyr; and two independent experiments for Asp, His, Cys, and Lys. For all of the titrations, the error in the pK value from fitting the experimental data to Equations 1 or 2 was <0.03.