| amino_acids | The 20 standard amino acids |
| amino_acids_properties | Amino acid side chain property values |
| amino_acid_pairs | Generate amino acid pairs |
| as_one_letter | Convert three-letter amino acid codes to one-letter codes |
| as_three_letter | Convert one-letter amino acid codes to three-letter codes |
| grantham_distance | Grantham distance |
| grantham_distances_matrix | Grantham distance matrix |
| grantham_equation | Grantham distance |