Chemical Properties
Following is a table listing the one-letter symbols, the three-letter symbols, and the chemical properties of the side-chains of the standard amino acids. The masses listed are based on weighted averages of the elemental isotopes at their natural abundances. Note that forming a peptide bond results in elimination of a molecule of water, so the mass of an amino acid unit within a protein chain is reduced by 18.01524 Da.
General chemical properties
| Amino Acid | Short | Abbrev. | Avg. Mass (Da) | pI | pK1 (α-COOH) |
pK2 (α-+NH3) |
|---|---|---|---|---|---|---|
| Alanine | A | Ala | 89.09404 | 6.01 | 2.35 | 9.87 |
| Cysteine | C | Cys | 121.15404 | 5.05 | 1.92 | 10.70 |
| Aspartic acid | D | Asp | 133.10384 | 2.85 | 1.99 | 9.90 |
| Glutamic acid | E | Glu | 147.13074 | 3.15 | 2.10 | 9.47 |
| Phenylalanine | F | Phe | 165.19184 | 5.49 | 2.20 | 9.31 |
| Glycine | G | Gly | 75.06714 | 6.06 | 2.35 | 9.78 |
| Histidine | H | His | 155.15634 | 7.60 | 1.80 | 9.33 |
| Isoleucine | I | Ile | 131.17464 | 6.05 | 2.32 | 9.76 |
| Lysine | K | Lys | 146.18934 | 9.60 | 2.16 | 9.06 |
| Leucine | L | Leu | 131.17464 | 6.01 | 2.33 | 9.74 |
| Methionine | M | Met | 149.20784 | 5.74 | 2.13 | 9.28 |
| Asparagine | N | Asn | 132.11904 | 5.41 | 2.14 | 8.72 |
| Pyrrolysine | O | Pyl | ||||
| Proline | P | Pro | 115.13194 | 6.30 | 1.95 | 10.64 |
| Glutamine | Q | Gln | 146.14594 | 5.65 | 2.17 | 9.13 |
| Arginine | R | Arg | 174.20274 | 10.76 | 1.82 | 8.99 |
| Serine | S | Ser | 105.09344 | 5.68 | 2.19 | 9.21 |
| Threonine | T | Thr | 119.12034 | 5.60 | 2.09 | |
| Valine | V | Val | 117.14784 | 6.00 | 2.39 | 9.74 |
| Tryptophan | W | Trp | 204.22844 | 5.89 | 2.46 | 9.41 |
| Tyrosine | Y | Tyr | 181.19124 | 5.64 | 2.20 | 9.21 |
Read more about this topic: Proteinogenic Amino Acids
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