Table 4 Most commonly used pKa values for the ionizable groups of proteins. Note that Bjellqvist and ProMoST use different amounts of additional pKa values (not shown), which take into account the relative position of the ionized group (whether it is located on the N- or C- terminus or in the middle). For more details, see References 4 and 5 and the “Theory” section on the IPC web site
Amino acid | NH2 | COOH | C | D | E | H | K | R | Y |
|---|---|---|---|---|---|---|---|---|---|
EMBOSS [29] | 8.6 | 3.6 | 8.5 | 3.9 | 4.1 | 6.5 | 10.8 | 12.5 | 10.1 |
DTASelect [30] | 8 | 3.1 | 8.5 | 4.4 | 4.4 | 6.5 | 10 | 12 | 10 |
Solomons [31] | 9.6 | 2.4 | 8.3 | 3.9 | 4.3 | 6 | 10.5 | 12.5 | 10.1 |
Sillero [32] | 8.2 | 3.2 | 9 | 4 | 4.5 | 6.4 | 10.4 | 12 | 10 |
Rodwell [33] | 8 | 3.1 | 8.33 | 3.68 | 4.25 | 6 | 11.5 | 11.5 | 10.07 |
Patrickios [34] | 11.2 | 4.2 | - | 4.2 | 4.2 | - | 11.2 | 11.2 | - |
Wikipedia | 8.2 | 3.65 | 8.18 | 3.9 | 4.07 | 6.04 | 10.54 | 12.48 | 10.46 |
Lehninger [35] | 9.69 | 2.34 | 8.33 | 3.86 | 4.25 | 6 | 10.5 | 12.4 | 10 |
Grimsley [15] | 7.7 | 3.3 | 6.8 | 3.5 | 4.2 | 6.6 | 10.5 | 12.04a | 10.3 |
Toseland [36] | 8.71 | 3.19 | 6.87 | 3.6 | 4.29 | 6.33 | 10.45 | 12 | 9.61 |
Thurlkill [37] | 8 | 3.67 | 8.55 | 3.67 | 4.25 | 6.54 | 10.4 | 12 | 9.84 |
Nozaki [38] | 7.5 | 3.8 | 9.5 | 4 | 4.4 | 6.3 | 10.4 | 12 | 9.6 |
Dawson [39] | 8.2b | 3.2b | 8.3 | 3.9 | 4.3 | 6 | 10.5 | 12 | 10.1 |
Bjellqvist [16] | 7.5 | 3.55 | 9 | 4.05 | 4.45 | 5.98 | 10 | 12 | 10 |
ProMoST [17] | 7.26 | 3.57 | 8.28 | 4.07 | 4.45 | 6.08 | 9.8 | 12.5 | 9.84 |
IPC_protein | 9.094 | 2.869 | 7.555 | 3.872 | 4.412 | 5.637 | 9.052 | 11.84 | 10.85 |
IPC_peptide | 9.564 | 2.383 | 8.297 | 3.887 | 4.317 | 6.018 | 10.517 | 12.503 | 10.071 |