Table 1.

Amino acid solubilities and apparent transfer Gibbs energies from water to 1 M proline and 2 M urea solutions

Amino acid	Solubility, g of AA/100 g solvent		Density at solubility limit		ΔGtr, cal/mol Water to 1 M proline	Δgtrsc Water to 1 M proline	Δgtrsc Water to 2 M urea‡
	Water†	1 M Proline	Water†	1 M Proline
Gly	25.1	20.00	1.08302	1.09603	102.63	0.00	0.00
Ala	16.6	13.29	1.04295	1.06416	104.28	1.65	−7.67
Phe	2.81	2.59	1.00528	1.03543	28.49	−74.14	−169.09
Trp	1.36	1.53	1.01	1.03367	−82.50	−185.14	−269.68
His	4.30	3.77	1.01206	1.04185	57.72	−44.91	−100.83
Tyr*	0.0469	0.0484	0.99705	1.02957	−33.88	−136.51	−89.94§
Met	5.69	4.95	1.01340	1.04211	61.82	−40.81	−102.36
Val	5.73	4.59	1.00951	1.03401	110.78	8.15	−43.12
Ile	3.35	2.73	1.00345	1.03366	100.10	−2.53	−76.66
Gln	4.19	3.50	1.01133	1.04071	85.69	−16.94	−94.29
Thr	9.74	8.11	1.02896	1.05459	85.05	−17.58	−43.43
Leu	2.15	1.74	1.00090	1.03187	104.90	2.27	−111.63
Asn	2.64	2.31	1.00746	1.03806	59.47	−43.16	−103.02
Ser	42.9	35.96	1.12805	1.13897	70.22	−32.42	−40.05
Pro	181.5	152.54	1.19418	1.19418	38.63	−64.01	−35.34
NaAsp	77.9	76.61	1.28523	1.27071	12.38	−90.25	7.35
NaGlu	62.4	60.49	1.21785	1.21323	13.66	−88.97	1.69
LysHCl	71.3	62.31	1.12780	1.13727	42.95	−59.68	−45.32
ArgHCl	85.3	74.07	1.15905	1.1668	42.64	−59.99	−42.14
DKP	1.68	1.43	1.00252	1.03382	75.77
DKP/2						37.89	−69.15

^*Solubilities determined spectrally. 

^†Data taken from Liu and Bolen (3). 

^‡Data taken from Wang and Bolen (4). 

^§Tyr data in 2 M urea were newly measured and not reported in the previous paper of Wang and Bolen (4). Δg_trsc represents the transfer Gibbs energy of indicated side chains determined from subtraction of the ΔG_tr of glycine from ΔG_tr of each of the other amino acids.