| Observed difference (percent) |
Evolutionary distance (PAMs / 100 millon years) |
| IG kappa chain C region | 37 |
| Kappa casein | 33 |
| Ig gamma chain C region | 31 |
| Lutropin beta chain | 30 |
| Ig lambda chain C region | 27 |
| Complement C3a anaphylatoxin | 27 |
| Lactalbumin | 27 |
| Epidermal growth factor | 26 |
| Somatotropin | 25 |
| Pancreatic ribonuclease | 21 |
| Lipotropin beta | 21 |
| Haptoglobin alpha chain | 20 |
| Serum albumin | 19 |
| Phospholipase A | 19 |
| Protease inhibitor, PSTI type | 18 |
| Prolactin | 17 |
| Pancreatic hormone | 17 |
| Carbonic anhydrase C | 16 |
| Lutropin alpha chain | 16 |
| Hemoglobin alpha chain | 12 |
| Hemoglobin beta chain | 12 |
| Lipid-binding protein A-II | 10 |
| Gastrin | 9.8 |
| Animal lysozyme | 9.8 |
| Myoglobin | 8.9 |
| Amyloid AA | 8.7 |
| Nerve growth factor | 8.5 |
| Acid proteases | 8.4 |
| Myelin basic protein | 7.4 |
| Thyrotropin beta chain | 7.4 |
| Parathyrin | 7.3 |
| Parvalbumin | 7.0 |
| Protease inhibitors, BPI type | 6.2 |
| Trypsin | 5.9 |
| Melanotropin beta | 5.6 |
| Alpha crystallin A chain | 5.0 |
| Endorphin | 4.8 |
| Cytochrome b | 4.5 |
| Insulin (except guinea pig and coypu) | 4.4 |
| Calcitonin | 4.3 |
| Neurophysin 2 | 3.6 |
| Plastocyanin | 3.5 |
| Adenylate kinase | 3.2 |
| Triosephosphate isomerase | 2.8 |
| Vasoactive intestinal peptide | 2.6 |
| Cytochrome c | 2.2 |
| Plant ferredoxin | 1.9 |
| Collagen (excluding nonrepetitive ends) | 1.7 |
| Troponin C. skeletal muscle | 1.5 |
| Alpha crystallin B chain | 1.5 |
| Glucagon | 1.2 |
| Glutamate dehydrogenase | 0.9 |
| Histone H2B | 0.9 |
| Histone H2A | 0.5 |
| Histone H3 | 0.14 |
| Histone H4 | 0.10 |
| Ubiquitin | 0.00 |
| Observed percentage difference | Evolutionary distance in PAM |
| 1 | 1 |
| 5 | 5 |
| 10 | 11 |
| 15 | 17 |
| 20 | 23 |
| 25 | 30 |
| 30 | 38 |
| 35 | 47 |
| 40 | 56 |
| 45 | 67 |
| 50 | 80 |
| 55 | 94 |
| 60 | 112 |
| 65 | 133 |
| 70 | 159 |
| 75 | 195 |
| 80 | 246 |
| 85 | 328 |
As the Evolutionary Distance increases, the probability of super-imposed mutation becomes greater resulting in a lower Observed Percent Difference. (Adapted from Table 23. Atlas of Protein Sequence and Structure, Suppl 3, 1978, M.O. Dayhoff, ed. National Biomedical Research Foundation, 1979.)