Table 1.

Median for substitution of the source amino acid (rows) for the destination amino acid (columns) in kcal/mol. Substitutions are labelled as radical, according to the kcal/mol criterion, but as conservative when the polarity-volume criterion is used, shown in green. Those considered as radical, regardless of the criterion used, are shown in red. On the other hand, substitutions classified as conservative by both criteria are shown in blue. Finally, substitutions considered conservative by the energy criterion, but as radical when the polarity–volume criterion was used, are indicated in purple.

	A	R	N	D	C	Q	E	G	H	I	L	K	M	F	P	S	T	W	Y	V
A	.	−0.12	0.15	0.41	0.32	−0.07	0.09	0.72	0.25	0.28	−0.16	−0.15	−0.30	−0.12	2.43	0.22	0.53	0.04	−0.05	0.50
R	0.66	.	0.58	0.97	0.82	0.33	0.63	1.16	0.66	0.60	0.17	0.13	0.08	0.24	2.88	0.74	0.94	0.43	0.33	0.93
N	0.35	−0.06	.	0.34	0.42	0.08	0.25	0.67	0.34	0.40	−0.08	−0.08	−0.17	−0.07	2.47	0.39	0.66	0.16	0.01	0.69
D	0.32	0.12	0.17	.	0.43	0.12	0.07	0.62	0.32	0.43	0.01	0.05	−0.07	0.00	1.81	0.42	0.65	0.23	0.09	0.69
C	0.20	0.45	0.36	0.89	.	0.41	0.78	1.14	0.61	0.31	−0.14	0.22	−0.28	0.65	2.69	0.54	0.45	1.56	1.00	0.29
Q	0.38	−0.03	0.34	0.62	0.53	.	0.23	0.91	0.37	0.20	−0.13	−0.06	−0.29	−0.05	2.57	0.49	0.63	0.11	0.05	0.58
E	0.29	0.02	0.34	0.43	0.53	0.03	.	0.81	0.29	0.17	−0.18	−0.07	−0.27	−0.12	1.90	0.47	0.57	0.05	−0.03	0.49
G	2.12	1.91	2.10	2.37	2.36	2.31	2.47	.	2.47	3.59	2.26	2.04	2.05	2.31	5.31	2.06	3.11	2.57	2.43	3.65
H	0.36	−0.11	0.23	0.66	0.42	0.04	0.32	0.92	.	0.21	−0.33	−0.18	−0.50	−0.39	2.61	0.48	0.58	−0.11	−0.23	0.51
I	2.02	1.43	2.03	2.80	1.88	1.61	2.10	3.06	1.62	.	0.06	1.20	0.05	0.83	3.95	2.49	1.73	1.54	1.23	0.81
L	1.67	1.13	1.73	2.34	1.81	1.35	1.70	2.61	1.46	0.78	.	0.93	−0.01	0.44	3.97	2.07	1.91	0.98	0.77	1.48
K	0.50	0.05	0.46	0.79	0.71	0.21	0.46	1.02	0.51	0.21	0.01	.	−0.09	0.07	2.52	0.62	0.80	0.26	0.16	0.75
M	1.24	0.82	1.27	1.68	1.49	0.95	1.16	2.04	1.16	0.76	0.19	0.65	.	0.42	3.65	1.48	1.58	0.66	0.63	1.34
F	2.78	2.32	2.89	3.70	2.73	2.52	3.03	3.78	2.30	1.91	0.90	2.07	0.63	.	4.59	3.13	2.95	0.94	0.50	2.42
P	0.90	0.63	0.90	0.80	1.00	0.70	0.58	1.02	0.77	0.94	0.68	0.65	0.64	0.64	.	0.94	1.06	0.75	0.71	1.12
S	−0.01	−0.24	−0.01	0.12	0.09	−0.15	−0.04	0.29	0.10	0.26	−0.18	−0.24	−0.29	−0.18	1.90	.	0.26	0.00	−0.11	0.48
T	0.15	−0.18	0.11	0.31	0.20	−0.08	0.06	0.55	0.11	−0.07	−0.28	−0.21	−0.37	−0.19	1.88	0.21	.	0.03	−0.10	0.11
W	2.49	2.12	2.64	3.24	2.56	2.32	2.67	3.43	2.13	1.86	0.99	1.96	0.73	0.51	4.16	2.93	2.76	.	0.82	2..30
Y	1.97	1.53	2.00	2.71	2.03	1.77	2.15	2.97	1.66	1.38	0.42	1.29	0.26	−0.06	4.12	2.46	2.27	0.45	.	1.79
V	0.94	0.42	0.99	1.44	0.91	0.60	0.92	1.93	0.73	−0.27	−0.18	0.28	−0.17	0.17	2.87	1.37	0.71	0.61	0.38	.