Table 2.

TMAO-solute interaction free energies

Solute	μ23/RT, m−1	${\mu }_{23}^{\mathit{\text{ex}}}$, cal/mol/m (25 °C)
purine	0.1425 ± 0.018	94.7 ± 10.6
cytidine	0.161 ± 0.024	106 ± 14
uridine	0.145 ± 0.017	96 ± 10
glycerol	−0.0503 ± 0.0072	−17.3 ± 4.2
Potassium dimethylphosphate	0.322 ± 0.027	211 ± 16
KCl	−0.0018 ± 0.015	-
amino acid side chain		ΔGtransfer, cal/mol/mb
Ala		−13.6
Leu		10.8
Phe		−8.65
Trp		−141.8
Tyr		−106.0
His		39.0
Arg		−101.4

^aμ₂₃/RT is the slope of ΔOsm (eq 7) plotted as in Figure 4B. ${\mu }_{23}^{\mathit{\text{ex}}}$ is calculated from μ₂₃/RT at 25 °C and includes a correction for the ideal entropy of mixing. See Background (eq 7–9) and Materials and Methods for details.

^bTransfer free energies based on relative solubilities of amino acids in water and 1 M TMAO, taken from reference ⁸. The transfer free energy of glycine has been subtracted, so ΔG_transfer applies to the amino acid side chain. The partial molar volume of TMAO⁶⁸ was used to transform ΔG_transfer from molar to molal units.