Edsall JT & Wyman J, 1958

John Edsall and Jeffries Wyman report a nearly complete set of amino acid pK values in their 1958 text Biophysical Chemistry (1). The values they report are drawn from various sources, but largely depend on data published earlier by Cohen and Edsall (2). These data are based on measurements of free amino acids and short peptides.

Amino acid pK values from Edsall JT & Wyman J, 1958 (1).

Group

3.24

†

ASP

3.910

‡

GLU

4.324

HIS

6.00

8.02

€

CYS

8.30

TYR

10.95

LYS

10.79

ARG

12.5

† Data from Table IV, chp. 8, p. 466. This value is derived from these data by determining the mean value of the carboxyl group pK values from the reported L peptides.

‡ Data from Table III, chp. 8, p. 452.

¶ Data from Table I, chp. 9, p. 495.

§ Data from Table VI, chp. 8, p. 464.

€ Data from Table VI, chp. 8, p. 466. This value is derived from these data by determing the mean value of the amino group pK values from the reported L peptides.

¥ Data from Table VI, chp. 8, p. 465 and Table IV, chp. 9, p. 498.

* Data from Table VI, chp. 8, p. 465.

æ Data from Table VI, chp. 8, p. 465. This value is reported as ca. 12.5 due to difficulty in observing the deprotonated guanido group at high pH values.