| Initial residue | Modification type | Modified residue | Chemical compound |
 ARG |
METY | RMN | omega-N-methylarginine (0) |
| ARG |
MS2N | RSM | symmetric-dimethylarginine (0) |
| ARG |
MS2C | RMS | symmetric-dimethylarginine (+1) |
| ARG |
MA2N | RAM | asymmetric-dimethylarginine (0) |
| ARG |
MA2C | RMA | asymmetric-dimethylarginine (+1) |
| ARG |
CITR | RCI | citrulline |
| ARG |
PHOS | R0P | phosphoarginine (0) |
| ARG |
GSAL | GSA | glutamic semialdehyde |
| ARG |
PHO2 | R1P | phosphoarginine (-1) |
| ARG |
ME1C | RMC | omega-N-methylarginine (+1) |
| ASN |
HYDR | N3H | 3-hydroxyasparagine (R) |
| ASN |
HYDS | NH3 | 3-hydroxyasparagine (S) |
| ASN |
DEAC | ASP | aspartic acid (-1) |
| ASN |
NGLY | NNG | N-acetylglucosamine |
| ASN |
METY | NME | N4-methylasparagine |
| ASP |
PHO2 | D2P | phosphoaspartate (-2) |
| ASP |
HYDR | DN3 | 3-hydroxyaspartate (0, R) |
| ASP |
HYCS | D3H | 3-hydroxyaspartate (-1, S) |
| ASP |
HYDC | DH3 | 3-hydroxyaspartate (-1, R) |
| ASP |
PHOS | D1P | phosphoaspartate (-1) |
| ASP |
HYDS | D3N | 3-hydroxyaspartate (0, S) |
| ASP |
METY | DMA | aspartate methyl ester |
| CYS |
CAAM | CAM | S-carbamoyl-cysteine |
| CYS |
METY | CYM | S-methylcysteine |
| CYS |
SULF | CSE | cysteic acid |
| CYS |
NITR | CSN | S-nitrosocysteine |
| CYS |
OXID | CSA | cysteine sulfinic acid |
| CYS |
HYDR | CYH | cysteine sulfenic acid |
| GLN |
HYDS | QH4 | 4-hydroxyglutamine (S) |
| GLN |
HYDR | Q4H | 4-hydroxyglutamine (R) |
| GLN |
DEAC | GLU | glutamic acid (-1) |
| GLN |
METY | QME | N5-methylglutamine |
| GLU |
CARB | ECA | 4-carboxyglutamate (-2) |
| GLU |
CARN | ECN | 4-carboxyglutamate (-1) |
| GLU |
METY | EME | glutamate methyl ester |
| HIS |
PH11 | H11 | 1-phosphohistidine (-1) |
| HIS |
PH12 | H12 | 1-phosphohistidine (-2) |
| HIS |
M11N | H1M | 1-methylhistidine (0) |
| HIS |
M13C | H3C | 3-methylhistidine (+1) |
| HIS |
M11C | H1C | 1-methylhistidine (+1) |
| HIS |
PH31 | H31 | 3-phosphohistidine (-1) |
| HIS |
PH32 | H32 | 3-phosphohistidine (-2) |
| HIS |
H2DC | ASP | aspartic acid (-1) |
| HIS |
H2NN | ASN | asparagine |
| HIS |
M13N | H3M | 3-methylhistidine (0) |
| HIS |
OXID | H2X | 2-oxo-histidine |
| LEU |
NORL | LNO | norleucine |
| LEU |
HYD3 | L3H | 3-hydroxyleucine (R) |
| LEU |
HYD5 | L5H | 5-hydroxyleucine (R) |
| LEU |
HY5S | LH5 | 5-hydroxyleucine (S) |
| LEU |
HYD4 | L4H | 4-hydroxyleucine |
| LEU |
HY3S | LH3 | 3-hydroxyleucine (S) |
| LYS |
NORL | LNO | norleucine |
| LYS |
HYDC | KPH | 5-hydroxylysine (+1, R) |
| LYS |
HYEM | KB2 | 2-hydroxybutyryl-lysine (S) |
| LYS |
PHO2 | K2P | phospholysine (-2) |
| LYS |
HYME | K2B | 2-hydroxybutyryl-lysine (R) |
| LYS |
LYSB | KLB | beta-lysyllysine |
| LYS |
LYSA | KLA | alpha-lysyllysine |
| LYS |
HYPS | KHS | hypusine (S) |
| LYS |
HYPR | KHR | hypusine (R) |
| LYS |
HYBE | KHB | 2-hydroxyisobutyryl-lysine |
| LYS |
PHOS | K1P | phospholysine (-1) |
| LYS |
MET3 | K3C | N6,N6,N6-trimethyllysine |
| LYS |
CAAM | KAM | homocitrulline |
| LYS |
CARB | KCA | carboxylysine (-1) |
| LYS |
CARN | KCN | carboxylysine (0) |
| LYS |
HYCS | KHP | 5-hydroxylysine (+1, S) |
| LYS |
HYDR | KH5 | 5-hydroxylysine (0, R) |
| LYS |
HYDS | K5H | 5-hydroxylysine (0, S) |
| LYS |
METY | KMN | methyllysine (0) |
| LYS |
ME1C | KMC | N6-methyllysine (+1) |
| LYS |
MET2 | K2M | N6,N6-dimethyllysine (0) |
| LYS |
ME2C | K2C | N6,N6-dimethyllysine (+1) |
| LYS |
ALLY | KAL | allysine |
| LYS |
ACET | KAC | N-acetyllysine |
| MET |
OXIS | MXS | methionine sulfoxide (S) |
| MET |
OXID | MSX | methionine sulfoxide (R) |
| MET |
SULF | MES | methionine sulfone |
| MET |
NORL | LNO | norleucine |
| PHE |
HYDD | F23 | 2,3-dihydroxyphenylalanine |
| PHE |
HYD2 | F2H | 2-hydroxyphenylalanine |
| PHE |
HYD3 | F3H | 3-hydroxyphenylalanine |
| PHE |
HYD4 | TYR | tyrosine |
| PRO |
HYD5 | PH5 | 5-hydroxyproline (R) |
| PRO |
HY5S | P5H | 5-hydroxyproline (S) |
| PRO |
HYDD | PHH | 3,4-dihydroxyproline |
| PRO |
HY4S | HY2 | 4-hydroxyproline (R) |
| PRO |
HYD4 | HYP | 4-hydroxyproline (S) |
| PRO |
OXID | PGA | pyroglutamic acid |
| PRO |
HY3S | P3H | 3-hydroxyproline (S) |
| PRO |
GSAL | GSA | glutamic semialdehyde |
| PRO |
HYD3 | PH3 | 3-hydroxyproline (R) |
| SER |
DEHY | SDH | dehydroalanine |
| SER |
OGLY | SOG | serine-O-acetylglucosamine |
| SER |
PHOS | S1P | phosphoserine (-1) |
| SER |
PHO2 | S2P | phosphoserine (-2) |
| THR |
PHO2 | T2P | phosphothreonine (-2) |
| THR |
OGLY | TOG | threonine-O-acetylglucosamine |
| THR |
OXID | TOX | 2-amino-3-ketobutyric acid |
| THR |
DEHY | TDH | 2,3-didehydrobutyrine |
| THR |
PHOS | T1P | phosphothreonine (-1) |
| TRP |
HYD6 | W6H | 6-hydroxytryptophan |
| TRP |
HYD4 | W4H | 4-hydroxytryptophan |
| TRP |
HYD7 | W7H | 7-hydroxytryptophan |
| TRP |
BROM | WBR | 6-bromotryptophan |
| TRP |
FOKY | WKF | formyl-kynurenine |
| TRP |
HYD5 | W5H | 5-hydroxytryptophan |
| TRP |
NITR | WNI | 6-nitrotryptophan |
| TRP |
KYNU | WKY | kynurenine |
| TRP |
HYKY | WKH | 3-hydroxykynurenine |
| TRP |
HYD2 | W2H | 2-hydroxytryptophan |
| TYR |
NITN | YNN | nitrotyrosine (0) pre-revised |
| TYR |
CHLO | YCH | chlorotyrosine |
| TYR |
NITR | YNI | nitrotyrosine (-1) |
| TYR |
SULF | YSU | sulfotyrosine |
| TYR |
PHO2 | Y2P | phosphotyrosine (-2) |
| TYR |
PHOS | Y1P | phosphotyrosine (-1) |
| TYR |
NITO | YNB | nitrotyrosine (neutral) old |
| TYR |
HYDR | HTY | 3,4-dihydroxyphenylalanine |
| VAL |
HYD3 | V3H | 3-hydroxyvaline |
In addition, a set of terminal modifications is also available.