Segel IH, 1976

Segel provides a nearly complete set of pK values in the second edtion of his classic textbook on laboratory calculations, Biochemical Calculations: How to Solve Mathematical Problems in General Biochemistry (1976) (1). The pK values are for the free amino acids in solution.

Amino acid pK values from Segel IH, 1976 (1).

Group

pK

CT

2.18

†‡

ASP

3.86

†

GLU

4.25

†

HIS

6.0

†

NT

9.53

†¶

CYS

8.33

†

TYR

10.07

†

LYS

10.53

†

ARG

12.48

†

† Data from Appendix IV.

‡ This value is derived from these data by determining the mean value of the α-carboxylic acid pK values for the twenty α-amino acids commonly found in proteins listed in Appendix IV.

¶ This value is derived from these data by determining the mean value of the α-amino group pK values for the twenty α-amino acids commonly found in proteins listed in Appendix IV.

References

(1) Segel, IH (1976) Biochemical Calculations: How to Solve Mathematical Problems in General Biochemistry, Second Edition, John Wiley & Sons, New York