Table 7.

Physicochemical properties and groupings of amino acids.

Property	Grouping
	Class 1 (C1)	Class 2 (C2)	Class 3 (C3)
Hydrophobicity	Polar R, K, E, D, Q, N	Neutral G, A, S, T, P, H, Y	Hydrophobic C, L, V, I, M, F, W
Normalized van der Waals volume	Volume range 0-2.78 G, A, S, T, P, D	Volume range 2.95-4.0N, V, E, Q, I, L	Volume range 4.03-8.08 M, H, K, F, R, Y, W
Polarity	Polarity value 4.9-6.2 L, I, F, W, C, M, V, Y	Polarity value 8.0-9.2 P, A, T, G, S	Polarity value 10.4-13 H, Q, R, K, N, E, D
Polarizability	Polarizability value 0-0.108 G, A, S, D, T	Polarizability value 0.128-0.186 C, P, N, V, E, Q, I, L	Polarizability value 0.219-0.409 K, M, H, F, R, Y, W
Charge	Positive K, R	Neutral A, N, C, Q, G, H, I, L, M, F, P, S, T, W, Y, V	Negative D, E
Secondary structure	Helix E, A, L, M, Q, K, R, H	Strand V, I, Y, C, W, F, T	Coil G, N, P, S, D
Solvent accessibility	Buried A, L, F, C, G, I, V, W	Exposed P, K, Q, E, N, D	Intermediate M, P, S, T, H, Y