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(-) Individual Properties of the 20 Standard Amino Acids

(-) Properties and Images

Amino Acid Name 3-letter Code 1-letter Code Mass
[dalton] 
Surface
2]
Volume
3]
pKa
(sidechain) 
pI
(at 25°C) 
Solubility
[g/100g] (at 25°C) 
Crystal Density
Alanine Ala A 71.09 115 88.6 - 6.107 16.65 1.401
Arginine Arg R 156.19 225 173.4 ~12 10.76 15.0 1.100
Aspartic Acid Asp D 115.09 150 111.1 4.5 2.98 0.778 1.660
Asparagine Asn N 114.11 160 114.1 - - 3.53 1.540
Cysteine Cys C 103.15 135 108.5 9.1-9.5 5.02 very high -
Glutamic Acid Glu E 129.12 190 138.4 4.6 3.08 0.864 1.460
Glutamine Gln Q 128.14 180 143.8 - - 2.5 -
Glycine Gly G 57.05 75 60.1 - 6.064 24.99 1.607
Histidine His H 137.14 195 153.2 6.2 7.64 4.19 -
Isoleucine Ile I 113.16 175 166.7 - 6.038 4.117 -
Leucine Leu L 113.16 170 166.7 - 6.036 2.426 1.191
Lysine Lys K 128.17 200 168.6 10.4 9.47 very high -
Methionine Met M 131.19 185 162.9 - 5.74 3.381 1.340
Phenylalanine Phe F 147.18 210 189.9 - 5.91 2.965 -
Proline Pro P 97.12 145 112.7 - 6.3 162.3 -
Serine Ser S 87.08 115 89.0 - 5.68 5.023 1.537
Threonine Thr T 101.11 140 116.1 - - very high -
Tryptophan Trp W 186.12 255 227.8 - 5.88 1.136 -
Tyrosine Tyr Y 163.18 230 193.6 9.7 5.63 0.0453 1.456
Valine Val V 99.14 155 140.0 - 6.002 8.85 1.230
Hyperlinks
Amino Acid Name : NIST Chemistry WebBook entry
3-letter Code : GIF image
1-letter Code : VRML
Data Sources
Surface : C.Chothia, J. Mol. Biol., 105(1975)1-14
Volume : A.A. Zamyatin, Prog. Biophys. Mol. Biol., 24(1972)107-123
pKa : C. Tanford, Adv. Prot. Chem., 17(1962)69-165
pI : The Merck Index, Merck & Co. Inc., Nahway, N.J., 11(1989); CRC Handbook of Chem.& Phys., Cleveland, Ohio, 58(1977)
Solubility : The Merck Index, Merck & Co. Inc., Nahway, N.J., 11(1989); CRC Handbook of Chem.& Phys., Cleveland, Ohio, 58(1977)
Crystal Density : The Merck Index, Merck & Co. Inc., Nahway, N.J., 11(1989); CRC Handbook of Chem.& Phys., Cleveland, Ohio, 58(1977)

(-) Qualitative Classification of the 20 Standard Amino Acids (JPEG)

(-) Hydrophobicity Scales

Amino Acid Estimated Hydrophobic Effect
Name  Residue Non-polar Surface Area a
2]
For Residue Burial 
[kcal/mol] 
For Side Chain Burial b
[kcal/mol] 
Glycine Gly G 47 1.18 0.0
Alanine Ala A 86 2.15 1.0
Valine Val V 135 3.38 2.2
Isoleucine Ile I 155 3.88 2.7
Leucine Leu L 164 4.10 2.9
Proline Pro P 124 3.10 1.9
Cysteine Cys C 48 1.20 0.0
Methionine Met M 137 3.43 2.3
Phenylalanine Phe F 39+155 3.46 2.3
Tryptophan Trp W 37+199 4.11 2.9
Tyrosine Tyr Y 38+116 2.81 1.6
Histidine His H 43+86 2.45 1.3
Threonine Thr T 90 2.25 1.1
Serine Ser S 56 1.40 0.2
Glutamine Gln Q 66 1.65 0.5
Asparagine Asn N 42 1.05 -0.1
Glutamic Acid Glu E 69 1.73 0.5
Aspartic Acid Asp D 45 1.13 -0.1
Lysine Lys K 122 3.05 1.9
Arginine Arg R 89 2.23 1.1

Source: P.A.Karplus, Protein Science 6(1997)1302-1307
a All surfaces associated with main- and side-chain carbon atoms were included except for amide, carboxylate and guanidino carbons. For aromatic side chains, the aliphatic and aromatic surface areas are reported seperately.
b The values are obtained from the previous column by subtracting the value for Gly (1.18 kcal/mol) from each residue.

(-) All 20 Standard Amino Acids in One Image (GIF)

(-) Properties of Amino Acids in Proteins

(-) Solvent Accessibility of Amino Acids in Known Protein Structures

Solvent Exposed Area (SEA)

The solvent accessibility information was derived from (a). The data for this table was calculated from 55 proteins (5624 residues) in the Brookhaven data base in 1991. The only clear trend in this table is that some residues, such as R and K, locate themselves so that they have access to the solvent. The hydrophobic residues, such as L and F, show no clear trend: they are found near the solvent as often as they are found buried.

Amino Acid Solvent Exposed area (SEA)
Name >30 Å2 (exposed) <10 Å2 (buried) 10-30 Å2
Alanine Ala A 48% 35% 17%
Arginine Arg R 84% 5% 11%
Aspartic Acid Asp D 81% 9% 10%
Asparagine Asn N 82% 10% 8%
Cysteine Cys C 32% 54% 14%
Glutamic Acid Glu E 93% 4% 3%
Glutamine Gln Q 81% 10% 9%
Glycine Gly G 51% 36% 13%
Histidine His H 66% 19% 15%
Isoleucine Ile I 39% 47% 14%
Leucine Leu L 41% 49% 10%
Lysine Lys K 93% 2% 5%
Methionine Met M 44% 20% 36%
Phenylalanine Phe F 42% 42% 16%
Proline Pro P 78% 13% 9%
Serine Ser S 70% 20% 10%
Threonine Thr T 71% 16% 13%
Tryptophan Trp W 49% 44% 7%
Tyrosine Tyr Y 67% 20% 13%
Valine Val V 40% 50% 10%

a D. Bordo and P. Argos, J. Mol. Biol. 217(1991)721-729(The absolute residue counts from table 2 were converted into relative values.)

(-) Mutation Mass Shifts

  Mutated Residues
  Gly Ala Ser Pro Val Thr Cys Ile Leu Asn Asp Gln Lys Glu Met His Phe Arg Tyr Trp
Gly 14 30 40 42 44 46 56 56 57 58 71 71 72 74 80 90 99 106 129
Ala -14 16 26 28 30 32 42 42 43 44 57 57 58 60 66 76 85 92 115
Ser -30 -16 10 12 14 15 26 26 27 28 41 41 42 44 50 60 69 76 99
Pro -40 -126 -10 2 4 6 16 16 17 18 31 31 32 34 40 50 59 66 89
Val -42 -28 -12 -2 2 4 14 14 15 16 29 29 30 32 38 48 57 64 87
Thr -44 -30 -14 -4 -2 2 12 12 13 14 27 27 28 30 36 48 55 62 85
Cys -46 -32 -16 -6 -4 -2 10 10 11 12 25 25 26 28 34 44 53 60 83
Ile -56 -42 -26 -16 -14 -12 -10 0 1 2 15 15 16 18 24 34 43 50 73
Leu -56 -42 -26 -16 -14 -12 -10 0 1 2 15 15 16 18 24 34 43 50 73
Asn -57 -43 -27 -17 -15 -13 -11 -1 -1 1 14 14 15 17 23 33 42 49 72
Asp -58 -44 -28 -18 -16 -14 -12 -2 -2 -1 13 13 14 16 22 32 41 48 71
Gln -71 -57 -41 -31 -29 -27 -25 -15 -15 -14 -13 0 1 3 9 19 28 35 58
Lys -71 -57 -41 -31 -29 -27 -25 -15 -15 -14 -13 0 1 3 9 19 28 35 58
Glu -72 -58 -42 -32 -30 -28 -26 -16 -16 -15 -14 -1 -1 2 8 18 27 34 57
Met -74 -60 -44 -34 -32 -30 -28 -18 -18 -17 -16 -3 -3 -2 6 16 25 32 55
His -80 -66 -50 -40 -38 -36 -34 -24 -24 -23 -22 -9 -9 -8 -6 10 19 26 49
Phe -90 -76 -60 -50 -48 -46 -44 -34 -34 -33 -32 -19 -19 -18 -16 -10 9 16 39
Arg -99 -85 -69 -59 -57 -55 -53 -43 -43 -42 -41 -28 -28 -27 -25 -19 -9 7 30
Tyr -106 -92 -76 -66 -64 -62 -60 -50 -50 -49 -48 -35 -35 -34 -32 -26 -16 -7 23
Trp -129 -115 -99 -89 -87 -85 -83 -73 -73 -72 -71 -58 -58 -57 -55 -49 -39 -30 -23
Note:Clicking on a table cell marks or unmarks it. Clicking on a table header cell marks or unmarks the complete column/row.

(-) Graph of Suggested Amino Acid Substitutions (JPEG)

(-) Ramachandran Plots for Individual Residue Types

  Ramachandran plots from Uppsala University (PostScript | GIF)