| Name | Abbrev. | pKa (side chain) |
Formula Structure |
| Alanine | Ala A |
|
CH3-CH(NH2)-COOH |
| Arginine | Arg R |
12.48 | HN=C(NH2)-NH-(CH2)3-CH(NH2)-COOH
 |
| Asparagine | Asn N |
|
H2N-CO-CH2-CH(NH2)-COOH |
| Aspartic acid | Asp D |
3.90 | HOOC-CH2-CH(NH2)-COOH |
| Cysteine | Cys C |
8.37 | HS-CH2-CH(NH2)-COOH |
| Glutamine | Gln Q |
|
H2N-CO-(CH2)2-CH(NH2)-COOH
 |
| Glutamic acid | Glu E |
4.07 | HOOC-(CH2)2-CH(NH2)-COOH |
| Glycine | Gly G |
|
NH2-CH2-COOH |
| Histidine | His H |
6.04 | N=C-NH-C=C-CH2-CH(NH2)-COOH |________|  |
| Isoleucine | Ile I |
|
CH3-CH2-CH(CH3)-CH(NH2)-COOH |
| Leucine | Leu L |
|
(CH3)2-CH-CH2-CH(NH2)-COOH |
| Lysine | Lys K |
10.54 | H2N-(CH2)4-CH(NH2)-COOH |
| Methionine | Met M |
|
CH3-S-(CH2)2-CH(NH2)-COOH
 |
| Phenylalanine | Phe F |
|
Ph-CH2-CH(NH2)-COOH
 |
| Proline | Pro P |
|
NH-(CH2)3-CH-COOH
|_________|  |
| Serine | Ser S |
|
HO-CH2-CH(NH2)-COOH
 |
| Threonine | Thr T |
|
CH3-CH(OH)-CH(NH2)-COOH
 |
| Tryptophan | Trp W |
|
Ph-NH-CH-C-CH2-CH(NH2)-COOH
|_______|  |
| Tyrosine | Tyr Y |
10.46 | HO-p-Ph-CH2-CH(NH2)-COOH
 |
| Valine | Val V |
|
CH3-CH(CH2)-CH(NH2)-COOH
 |