| d-Ala | D form of Alanine |
| d-Arg | D form of Arginine |
| d-Asn | D form of Asparagine |
| d-Asp | D form of Aspartic Acid |
| d-Cys | D form of Cysteine |
| d-Glu | D form of Glutamic Acid |
| d-Gln | D form of Glutamine |
| HCY | Homocysteine |
| d-His | D form of Histidine |
| HSE | Homoserine |
| d-HSE | D form of Homoserine |
| d-Ile | D form of Isoleucine |
| d-Leu | D form of Leucine |
| d-Lys | D form of Lysine |
| d-Met | D form of Methionine |
| NLE | Norleucine |
| d-NLE | D form of Norleucine |
| NVA | Norvaline |
| d-NVA | D form of Norvaline |
| Orn | Ornithine |
| d-Orn | D form of Ornithine |
| Pen | Penicillamine |
| d-Pen | D form of Penicillamine |
| d-Phe | D form of Phenylalanine |
| d-Pro | D form of Proline |
| d-Ser | D form of Serine |
| d-Thr | D form of Threonine |
| d-Trp | D form of Tryptophan |
| d-Tyr | D form of Tyrosine |
| d-Val | D form of Valine |
| pGlu | Pyro Glutamate |
| Lys(Dnp) | Dinitrobenzylation of Lysine |
| pThr | Phosphorylation of Threonine |
| pSer | Phosphorylation of Serine |
| pTyr | Phosphorylation of Tyrosine |
| gamma-Glu | Gamma-Glutamate |
| d-gamma-Glu | D-Gamma-Glutamate |
| Cit | Citrulline |
| NMe-Ala | N-methylated Alanine |
| NMe-Ile | N-methylated Isoleucine |
| NMe-Leu | N-methylated Leucine |
| NMe-Phe | N-methylated Phenylalanine |
| NMe-Val | N-methylated Valine |
| NMe-Ser | N-methylated Serine |
| NMe-Thr | N-methylated Threonine |
| NMe-Tyr | N-methylated Tyrosine |
| alpha-ABA | Alpha Amino-Butyric Acid |
| Beta-Asp | Beta-Aspartic acid |
| Ac-Lys | Acetylation at alpha amine group |
| 2-Me-Ala | 2-Methyl Alanine |
| NMe-Gly | N-methylated Glycine |
| Lys(biotin) | Biotin Lysine |
| Cys(Acm) | Acetaminomethyl Cysteine |
| Cys(tBu) | t-Butyl Cysteine |
| d-1-NAL | (D) 1-Naphthylalanine |
| L-1-NAL | (L) 1-Naphthylalanine |
| d-2-PAL | Pyridyl-D-alanine |
| L-2-PAL | Pyridyl-L-alanine |
| d-4-Cl-Phe | Chloro-D-phenylalanine |
| L-4-Cl-Phe | Chloro-L-phenylalanine |
| ABU | Aminobutyric Acid |
| AIB | Aminoisobutyric acid |
| MPA | Mercaptopropionic acid |
| HYP | Hydroxy Proline |
| Lys-Ac | Acetylation at the side chain |
| Cha | Cyclohexylalanine |
| Chg | Cyclohexylglycine |
| D-2-Me-Trp | D form of Methyl Trp |
| D-2-Nal | D form of 2-Nal |
| D-3-Pal | D form of 3-Pal |
| D-4-F-Phe | D form of Fluoro Phe |
| D-4-I-Phe | D form of Iodo Phe |
| D-4-NO2-Phe | D form of Nitro Phe |
| D-4-Pal | D form of 4-Pal |
| D-Beta-Asp | D form of Beta-Asp |
| D-Cha | D form of Cha |
| D-Chg | D form of Chg |
| D-Cit | D form of Cit |
| Dab | Diaminobutyric Acid |
| Dap | Diaminopropionic Acid |
| L-2-Nal | L form of 2-Nal |
| L-3-Pal | L form of 3-Pal |
| L-4-F-Phe | L form of 4-F-Phe |
| L-4-I-Phe | L form of 4-I-Phe |
| L-4-NO2-Phe | L form of 4-NO2-Phe |
| L-4-Pal | L form of 4-Pal |
| Lys(5-FAM) | Lys(5-FAM) |
| Lys(Dansyl) | Lys(Dansyl) |
| Lys(Me) | Methyl Lys |
| Lys(Me2) | Dimethyl Lys |
| Lys(Me3) | Trimethyl Lys |
| Lys(TMR) | Lys(TMR) |
| NMe-Asp | N-methyl Asp |
| NMe-Glu | N-methyl Glu |
| NMe-Nle | N-methyl Nle |
| NMe-Nva | N-methyl Nva |
| Phg | Phenylglycine |
| Ser(octanoic-acid) | Ser(octanoic-acid) |
| d-HCY | Homocysteine |
| d-pGlu | Pyroglutamate |
| nme-Met | N-methylated Methionine |
| Mini-PEG1 | Mini form of PEG1 |
| Met(O) | Methionine sulfoxide |
| Met(O)2 | Methionine sulfone |
| Cpg | Cyclopentylglycine |
| Pra | Propargylglycine |
| Tic | 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic acid |
| Sec | Selenocysteine |
| Se-Met | Selenomethionine |
| Lys(N3) | Azido-Lysine |
| Beta-HomoLeu | Beta-HomoLeucine |
| Cys(Cam) | Carboxyamidomethylated Cysteine |
| Arg(Me) | Methylation at the side chain of Arginine |
| ADMA | Arg(Me)2 asymmetrical |
| SDMA | Arg(Me)2 symmetrical |
| Beta-Ala | Beta-Alanine |
| GABA | 4-Aminobutyric acid |
| Ahx | 6-amino-hexanoic acid |
| PEG2 | NH2-(PEG)2-CH2COOH |
| PEG6 | NH2-(PEG)6-CH2CH2COOH |
| PEG11 | NH2-(PEG)11-CH2COOH |
| PEG12 | NH2-(PEG)12-CH2CH2COOH |
| Dab(Dnp) | |
| Dap(Dnp) | |
| Dpa | |
| Lys(Dde) | |
| Lys(ivdde) | |
| Oic | |
| Pip | |
| Tle |