| Name | Site | Modification | Change in mass, Dm |
| N-terminal acetylation | Terminal NH2- | Replaced by CH3CONH- | +42 |
| N-terminal formylation | Terminal NH2- | Replaced by HCONH- | +28 |
| N-terminal myristylation | Terminal NH2- | Replaced by CH3(CH2)12CONH- | +210 |
| N-terminal palmitoylation | Terminal NH2- | Replaced by CH3(CH2)14CONH- | +238 |
| C-terminal amidation | Terminal -COOH | Replaced by -CONH2 | -1 |
| Disulfide bonds | 2 Cys -SH | Replaced by -S-S- | -2 |
| Glycosylation (N-linked) | N-X-S/T | ||
| Glycosylation (O-linked) | S/T | ||
| Sulfation | -OH of Y | Replaced by -OSO3H | +80 |
| Phosphorylation | -OH of Y/S/T | Replaced by -OPO3H2 | +80 |
| N-methylation | -NH2 of K/R/H/Q | Replaced by -NHCH3 | +14 |
| O-methylesterification | -COOH of E/D | Replaced by -COOCH3 | +14 |
| Carboxylation | -NH2 of E/D | Replaced by -NHOCH3 | +30 |
| Hydroxylation | -NH2 of P/K/D | Replaced by -NHOH | +16 |