Amino Acid Residue Masses
Look up average and monoisotopic residue masses for the 20 standard amino acids and the terminal water correction.
Masses used by the calculator
For a single linear chain with free termini, add the selected mass for each residue and the water correction once. The values describe a neutral, unmodified chain with reduced cysteines.
| Group | Average (Da) | Monoisotopic (Da) |
|---|---|---|
| A | 71.0788 | 71.03711 |
| C | 103.1388 | 103.00919 |
| D | 115.0886 | 115.02694 |
| E | 129.1155 | 129.04259 |
| F | 147.1766 | 147.06841 |
| G | 57.0519 | 57.02146 |
| H | 137.1411 | 137.05891 |
| I | 113.1594 | 113.08406 |
| K | 128.1741 | 128.09496 |
| L | 113.1594 | 113.08406 |
| M | 131.1926 | 131.04049 |
| N | 114.1038 | 114.04293 |
| P | 97.1167 | 97.05276 |
| Q | 128.1307 | 128.05858 |
| R | 156.1875 | 156.10111 |
| S | 87.0782 | 87.03203 |
| T | 101.1051 | 101.04768 |
| V | 99.1326 | 99.06841 |
| W | 186.2132 | 186.07931 |
| Y | 163.1760 | 163.06333 |
| Water | 18.01524 | 18.01056 |