Amino acid | Codes | Relative abundance (mole%) (1) | MW (2) | pKa (3) |
---|---|---|---|---|
Parental | ||||
Glycine | gly G | 8.3 | 57.05 | |
Aliphatic | ||||
Proline | pro P | 3.4 | 97.12 | |
Alanine | ala A | 9.4 | 71.09 | |
Valine | val V | 5.8 | 99.13 | |
Leucine | leu L | 10.7 | 113.08 | |
Isoleucine | ile I | 5.7 | 113.16 | |
Aromatic | ||||
Phenylalanine | phe F | 4.8 | 147.18 | |
Tryptophan | trp W | 1.1 | 186.21 | |
Tyrosine | tyr Y | 2.9 | 163.18 | 9.6 |
Histidine | his H | 2.1 | 137.14 | 7.0 |
Sulfur | ||||
Cysteine | cys C | 2.5 | 103.15 | 8.5 |
Methionine | met M | 2.3 | 131.20 | |
Hydroxyl | ||||
Serine | ser S | 7.4 | 87.08 | 16 |
Threonine | thr T | 5.5 | 101.11 | 16 |
Strongly acidic | ||||
Aspartic acid | asp D | 4.6 | 115.09 | 4.7 |
Glutamic acid | glu E | 5.3 | 129.16 | 12 |
Strongly basic | ||||
Lysine | Iys K | 5.6 | 128.17 | 10.2 |
Arginine | arg R | 4.6 | 156.19 | 12 |
Amido | ||||
Aspargine | asn N | 4.3 | 114.10 | |
Glutamine | gln Q | 3.7 | 128.13 |
(1) Analysis of 9 proteins: insulin (bovine), lysozyme (chicken), mannitol permease & lactose permease
(E. coli), hemoglobin & cytochrome c (human), glucagon (pig), ferridoxin (spinach), wool (sheep).
(2) Isotopic average of neutral amino acyl residu in a peptide bond.
(3) In peptides in aqueous solution. N-terminus: pKa=7.8 & C-terminus: pKa=3.7.