Creighton TE, 1993

Creighton presents a complete set of pK values in his text Proteins: structures and molecular properties (1). The data used to generate these values are from a variety of authors and span both model compound and short peptide data (2-4). Creighton does warn that the pK values of the α-carboxyl and α-amino groups are highly dependent on the identity of the terminal amino acid.

Amino acid pK values from Creighton TE, 1993 (1).

Group

3.9

†‡

ASP

3.95

†¶

GLU

4.4

†§

HIS

6.5

†€

7.4

†¥

CYS

9.25

†*

TYR

10.15

†•

LYS

10.75

†£

ARG

12.0

†

† Data from Table 1.2.

‡ The reported range of pK values is 3.5–4.3. The value recorded here is the mean value of this range.

¶ The reported range of pK values is 3.9–4.0. The value recorded here is the mean value of this range.

§ The reported range of pK values is 4.3–4.5. The value recorded here is the mean value of this range.

€ The reported range of pK values is 6.0–7.0. The value recorded here is the mean value of this range.

¥ The reported range of pK values is 6.8–8.0. The value recorded here is the mean value of this range.

* The reported range of pK values is 9.0–9.5. The value recorded here is the mean value of this range.

• The reported range of pK values is 10.0–10.3. The value recorded here is the mean value of this range.

£ The reported range of pK values is 10.4–11.1. The value recorded here is the mean value of this range.