Table 2.

12 groups of amino acids.

Properties	Amino acids
Acidic	ASP, GLU
Basic	ARG, HIS, LYS
Neutral	ALA, GLY, ILE, LEU, MET, PHE, PRO, TRP, TYR, VAL
Aliphatic	ALA, GLY, ILE, LEU, VAL
Aromatic	HIS, PHE, TRP, TYR
Cyclic	HIS, PHE, PRO, TRP, TYR
Acyclic	ALA, ARG, ASN, ASP, CYS, GLU, GLN, GLY, ILE, LEU, LYS, MET, SER, THR, VAL
Hydrophobic	ALA, GLY, ILE, LEU, MET, PHE, PRO, TRP, TYR, VAL
Polar	ARG, ASN, ASP, CYS, GLU, GLN, HIS, LYS, SER, THR
Small	ALA, GLY, SER
Medium	ASN, ASP, CYS, PRO, THR, VAL
Large	ARG, GLU, GLN, HIS, ILE, LEU, LYS, MET, PHE, TRP, TYR