Percent of Deprotonated Amino Acid Side Chains over the pH Range Typically Used for Formulation of Protein Therapeutics (Calculated from the Henderson-Hasselbach Equation According to Skoog and Wichman, 1986)
| Residue | pKa | pH 4 | pH 5 | pH 6 | pH 7 |
|---|---|---|---|---|---|
| N-term | 7.6 | 0.03 | 0.25 | 2.45 | 20.08 |
| C-Term | 1.8 | 99.37 | 99.94 | 99.99 | 100.00 |
| Arg | 12 | 0.00 | 0.00 | 0.00 | 0.00 |
| Cys | 8.5 | 0.00 | 0.03 | 0.32 | 3.07 |
| Tyr | 13 | 0.00 | 0.00 | 0.00 | 0.00 |
| Lys | 10 | 0.00 | 0.00 | 0.01 | 0.10 |
| His | 6.5 | 0.32 | 3.07 | 24.03 | 75.97 |
| Glu | 4.4 | 28.47 | 79.92 | 97.55 | 99.75 |
| Asp | 4.4 | 28.47 | 79.92 | 97.55 | 99.75 |