Table 2.

Comparison of predicted and observed proline m-values for protein unfolding and µ₂₃ values for interaction of proline with native BSA surface

Protein Process	Proline			GB			Urea
	Experi- mental	α-value prediction	GTFE prediction 37	Experi- mental	α-value prediction	GTFE Predict- ion 37	Experi- mental	α-value predict- ion	GTFE Predict- ion 37
Ribonuclease T1 unfolding m-value (kcal mol−1 M−1)	0.8±0.1 22	1.1±0.5a	−0.03±0.6	0.6±0.1 22	0.7±1.1a	−0.2±0.7	−1.2±0.1 22	−2.0±0.2a	−1.2±0.6
α-chymo- trypsin unfolding m-value (kcal mol−1 M−1)	6.0±0.436	4.3±1.4a	1.8±2.2	5.6±0.336	3.9±3.1a	1.4±3.1	3.0±0.436	−4.5±0.5a	−4.4±2.0
Native BSA µ23 value (kcal mol−1 m−1)	11.9±0.3	7.7±2.0b	−6.6d	21.717	10.8±3.3b	−12.1d	−4.517	−3.6±0.8b	−2.3d

^aα-value predictions use an extended model of the unfolded state (see text)

^bα-value predictions use ASA calculated from PDB 1BM0¹⁸ and neglect interactions of the solute with the Na⁺ ions of the electroneutral BSA component.

^cCalculated as the initial slope of a quadratic fit of ∆G_obs vs urea molarity.³⁶

^dGTFE predictions use side chain and backbone values from ref 22 and ASA calculated from PDB 1BM0¹⁸; these predictions implicitly include counterions of charged amino acid side chains.³⁷