TABLE 4

Thermodynamic parameters of binding to the β₂-AR, using [³H]MFen as the marker ligand compared with the previously reported parameters obtained using [³H]CGP-12177 as the marker ligand (Jozwiak et al., 2010a)

Distance parameter is the Euclidean distance describing a shift of the (ΔH°; −TΔS°) point, determined in the [³H]MFen experiment with respect to the [³H]CGP-12177-derived point, as illustrated in Fig. 5.

	ΔH°		−TΔS°		ΔG°		Distance
	MFen	CGP	MFen	CGP	MFen	CGP	Distance
	kJ/mol		kJ/mol		kJ/mol
Propranolol	+5.98 ± 0.04	−4.5	−54.32 ± 0.04	−48.95	−48.3 ± 0.06	−53.5	11.8
(R)-Isoproterenol	+18.4 ± 0.13	−18.03	−67.9 ± 0.13	−19.5	−49.5 ± 0.2	−37.6	60.6
(R,R′)-Fen	+24.1 ± 0.52	0	−72.6 ± 1.4	−38.8	−48.5 ± 1.5	−38.8	41.5
(R,S′)-Fen	+15.3 ± 3.0	+7.1	−54.9 ± 1.2	−40.0	−39.6 ± 3.2	−31.1	17.0
(S,R′)-Fen	+18.4 ± 0.13	−23.0	−47.0 ± 1.1	−8.1	−32.7 ± 1.6	−31.1	53.9
(S,S′)-Fen	+16.2 ± 2.2	−35.8	−48.5 ± 2.2	+6.3	−32.2 ± 3.1	−29.5	75.6