.
Amino Acid | 3 Letter Code | 1 Letter Code | Structure | pKa1
(α-carboxyl) |
pka2 (α-amino) | pka3 (side chain) |
Nonpolar Side Chains |
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Glycine | Gly | G | 2.35 | 9.78 | . | |
Alanine | Ala | A | 2.35 | 9.87 | . | |
Valine | Val | V | 2.29 | 9.74 | . | |
Leucine | Leu | L | 2.33 | 9.74 | . | |
Isoleucine | Ile | I | 2.32 | 9.76 | . | |
Methionine | Met | M | 2.13 | 9.28 | . | |
Proline | Pro | P | 1.95 | 10.64 | . | |
Phenylalanine | Phe | F | 2.20 | 9.31 | . | |
Tryptophan | Trp | W | 2.46 | 9.41 | . | |
Uncharged Polar Side Chains |
||||||
Serine | Ser | S | 2.19 | 9.21 | . | |
Threonine | Thr | T | 2.09 | 9.10 | . | |
Asparagine | Asn | N | 2.14 | 8.72 | . | |
Glutamine | Gln | Q | 2.17 | 9.13 | . | |
Tyrosine | Tyr | Y | 2.20 | 9.21 | 10.46 | |
Cysteine | Cys | C | 1.92 | 10.70 | 8.37 | |
Charged Polar Side Chains10.54 |
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Lysine | Lys | K | 2.16 | 9.06 | 10.54 | |
Arginine | Arg | R | 1.82 | 8.99 | 12.48 | |
Histidine | His | H | 1.80 | 9.33 | 6.04 | |
Aspartic Acid | Asp | D | 1.99 | 9.90 | 3.90 | |
Glutamic Acid | Glu | E | 2.10 | 9.47 | 4.07 |