Table 1. The physicochemical and biochemical properties of the 20 amino acids.

Amino Acid	Polarity	Secondary structure	Molecular volume	Codon diversity	Electrostatic charge
A	−0.591	−1.302	−0.733	1.57	−0.146
C	−1.343	0.465	−0.862	−1.02	−0.255
D	1.05	0.302	−3.656	−0.259	−3.242
E	1.357	−1.453	1.477	0.113	−0.837
F	−1.006	−0.59	1.891	−0.397	0.412
G	−0.384	1.652	1.33	1.045	2.064
H	0.336	−0.417	−1.673	−1.474	−0.078
I	−1.239	−0.547	2.131	0.393	0.816
K	1.831	−0.561	0.533	−0.277	1.648
L	−1.019	−0.987	−1.505	1.266	−0.912
M	−0.663	−1.524	2.219	−1.005	1.212
N	0.945	0.828	1.299	−0.169	0.933
P	0.189	2.081	−1.628	0.421	−1.392
Q	0.931	−0.179	−3.005	−0.503	−1.853
R	1.538	−0.055	1.502	0.44	2.897
S	−0.228	1.399	−4.76	0.67	−2.647
T	−0.032	0.326	2.213	0.908	1.313
V	−1.337	−0.279	−0.544	1.242	−1.262
W	−0.595	0.009	0.672	−2.128	−0.184
Y	0.26	0.83	3.097	−0.838	1.512

Listed below are the scores of the physicochemical and biochemical properties of the 20 amino acids, each of which can be coded by a 5-dimensional vector.