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Amino Acid pKa and pI Values

Amino Acid pKaC pKaN pKaR pI
Glycine
Alanine
Valine
Leucine
Isoleucine
Proline
Serine
Threonine
Cysteine
Methionine
Asparagine
Glutamine
Phenylalanine
Tyrosine
Tryptophan
Lysine
Arginine
Histidine
Aspartate
Glutamate 		2.4
2.4
2.3
2.3
2.3
2.0
2.2
2.1
1.9
2.1
2.1
2.2
2.2
2.2
2.5
2.2
1.8
1.8
2.0
2.1 		9.8
9.9
9.7
9.7
9.8
10.6
9.2
9.1
10.7
9.3
8.7
9.1
9.3
9.2
9.4
9.1
9.0
9.3
9.9
9.5







8.4




10.5

10.5
12.5
6.0
3.9
4.1 		6.10
6.15
6.00
6.00
6.05
6.30
5.70
5.60
5.15
5.70
5.40
5.65
5.75
5.70
5.95
9.80
10.75
7.65
2.95
3.10