The Amino Acid Repository

                                        Chemical Properties and Images
                                                  Qualitative classification of the 20 Standard Amino Acids (JPG)
                                        Hydrophobicity scale
                                          Postranslational Modifications of Amino Acids in Proteins
                                                  Solvent Accessibility of Amino Acids in Protein Structures
                                                  Mutation Mass Shifts
                                                  Graph of Suggested Amino Acid Substitutions (JPG)
 

Individual properties and images of amino acidsa

Chemical Properties and Images (three letter code: GIF, one letter code: VRML)
 
amino acid    
 mass 
surface b
volume c
pKa d
pI e
solubility e
density e
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
1.1
Aspartic Acid ASP
D
114.11
150
111.1
4.5
2.98
0.778
1.66
Asparagine ASN
N
115.09
160
114.1
-
-
3.53
1.54
Cysteine CYS
C
103.15
135
108.5
9.1-9.5
5.02
very
-
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
20
168.6
10.4
9.47
very
-
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
-
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
a mass [dalton], surface [Å2], volume [Å3], pKa [side chain], pI [at 25°C], solubility [g/100g, 25°C], density [crystal density, g/ml],
  three letter code: GIF, one letter code: VRML

b C.Chothia, J. Mol. Biol., 105(1975)1-14

c A.A. Zamyatin, Prog. Biophys. Mol. Biol., 24(1972)107-123

d C. Tanford, Adv. Prot. Chem., 17(1962)69-165

e The Merck Index, Merck & Co. Inc., Nahway, N.J., 11(1989); CRC Handbook of Chem.& Phys., Cleveland, Ohio, 58(1977)
 
 back
 

 Hydrophopicity scale a
 
Residue non-polar 
surface area b 
[A2]		 Estimated hydrophobic effect 
for residue burial  
[kcal/mol] 		 Estimated hydrophobic effect 
for side chain burial c 
[kcal/mol] 
Gly  47 1.18 0.0
Ala 86 2.15 1.0
Val 135 3.38 2.2
Ile 155 3.88 2.7
Leu 164 4.10 2.9
Pro 124 3.10 1.9
Cys 48 1.20 0.0
Met 137 3.43 2.3
Phe 39+155 3.46 2.3
Trp 37+199 4.11 2.9
Tyr 38+116 2.81 1.6
His 43+86 2.45 1.3
Thr 90 2.25 1.1
Ser 56 1.40 0.2
Gln 66 1.65 0.5
Asn 42 1.05 -0.1
Glu 69 1.73 0.5
Asp 45 1.13 -0.1
Lys 122 3.05 1.9
Arg 89 2.23 1.1
  a  P.A.Karplus, Protein Science 6(1997)1302-1307
  b  All surfaces associated with main- and side-chain carbon atoms were included except for amide, carb-
      oxylate and guanidino carbons. For aromatic side chains, the aliphatic and aromatic surface areas are
      reported seperately.
  c  The values are obtained from the previous column by substracting the value for Gly (1.18 kcal/mol) from
      each residue.
 
back

 

Amino acids in proteins
 
Postranslational Modifications of Amino Acids in Proteins
Sulphydryls Disulfidebond
-2.0159
 Oxidation
+15.9994
(C,M) Cysteinylation
+119.1442
 Glutathionylation
+305.3117
Methylation
+14.0269
 Formylation
+28.0104
Acetylation
+42.0373
 Lipoic acid
+188.3147
Amines Farnesylation
+204.3556
 Myristoylation
+210.3598
(K/N) Biotinylation
+226.2994
 Palmitoylation
+238.4136
Stearoylation
+266.4674
 Geranylation
+272.4741
Acids & Pyroglutamic acid (Q)
-17.0306
 Deamidation (Q,N)
+0.9847
Amides(E/D/Q/N) Carboxylation (E,D)
+44.0098
Hydroxyl- Phosphorylation
+79.9799
 Sulphation
+80.0642
groups (S/T/Y)
Carbohydrates Pentoses
+132.1161
 Deoxyhexoses
+146.1430
(S/T/N) Hexosamines
+161.1577
 Hexoses
+162.1424
N-acetylhexosamines
+203.1950
 Sialic acid
+291.2579
 back 
 

Solvent accessibility of Amino Acids in known protein structuresa

SEA (Solvent Exposed Area)

The solvent accessibility information was derived from (a). The data for this table was calculated from 55 proteins in the Brookhaven data base. 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
SEA >30 Å2
SEA <10 Å2
30 Å2 > SEA >10 Å2
S
0.70
0.20
0.10
T
0.71
0.16
0.13
A
0.48
0.35
0.17
G
0.51
0.36
0.13
P
0.78
0.13
0.09
C
0.32
0.54
0.14
D
0.81
0.09
0.10
E
0.93
0.04
0.03
Q
0.81
0.10
0.09
N
0.82
0.10
0.08
L
0.41
0.49
0.10
I
0.39
0.47
0.14
V
0.40
0.50
0.10
M
0.44
0.20
0.36
F
0.42
0.42
0.16
Y
0.67
0.20
0.13
W
0.49
0.44
0.07
K
0.93
0.02
0.05
R
0.84
0.05
0.11
H
0.66
0.19
0.15
a D. Bordo and P. Argos, J. Mol. Biol. 217(1991)721-729

 back
 
 
 

Mutation Mass Shifts

Residues DOWN the left indicate the EXPECTED residues

Residues ACROSS the top indicate the MUTANT 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
57
58
71
72
74
80
90
99
106
129
Ala
-14
16
26
28
30
32
42
43
44
57
58
60
66
76
85
92
115
Ser
-30
-16
10
12
14
15
26
27
28
41
42
44
50
60
69
76
99
Pro
-40
-126
-10
2
4
6
16
17
18
31
32
34
40
50
59
66
89
Val
-42
-28
-12
-2
2
4
14
15
16
29
30
32
38
48
57
64
87
Thr
-44
-30
-14
-4
-2
2
12
13
14
27
28
30
36
48
55
62
85
Cys
-46
-32
-16
-6
-4
-2
10
11
12
25
26
28
34
44
53
60
83
Leu/Ile
-56
-42
-26
-16
-14
-12
-10
1
2
15
16
18
24
34
43
50
73
Asn
-57
-43
-27
-17
-15
-13
-11
-1
1
14
15
17
23
33
42
49
72
Asp
-58
-44
-28
-18
-16
-14
-12
-2
-1
13
14
16
22
32
41
48
71
Gln/Lys
-71
-57
-41
-31
-29
-27
-25
-15
-14
-13
1
3
9
19
28
35
58
Glu
-72
-58
-42
-32
-30
-28
-26
-16
-15
-14
-1
2
8
18
27
34
57
Met
-74
-60
-44
-34
-32
-30
-28
-18
-17
-16
-3
-2
6
16
25
32
55
His
-80
-66
-50
-40
-38
-36
-34
-24
-23
-22
-9
-8
-6
10
19
26
49
Phe
-90
-76
-60
-50
-48
-46
-44
-34
-33
-32
-19
-18
-16
-10
9
16
39
Arg
-99
-85
-69
-59
-57
-55
-53
-43
-42
-41
-28
-27
-25
-19
-9
7
30
Tyr
-106
-92
-76
-66
-64
-62
-60
-450
-49
-48
-35
-34
-32
-26
-16
-7
23
Trp
-129
-115
-99
-89
-87
-85
-83
-73
-72
-71
-58
-57
-55
-49
-39
-30
-23
 back