Table 4. Binding and Signalling Parameter Estimates for His1- and Phe1-Containing Chimeric Ligands^a.

	Equilibrium binding	cAMP			β-arrestin-2
	pKi (M)	pEC50 (M)	Emax (%)	log τ/KA (M)	pEC50 (M)	Emax (%)	log τ/KA (M)
GLP-1	8.5 ± 0.1	9.4 ± 0.1	100	9.3 ± 0.1	6.4 ± 0.2	111 ± 7	6.4 ± 0.1
GLP-1-phe1	6.9 ± 0.1*,#	8.1 ± 0.2*,#	100	8.1 ± 0.1*,#	5.7 ± 0.1*,#	61 ± 7*,#	5.4 ± 0.1*,#
Chi1	8.6 ± 0.1	9.5 ± 0.1	100	9.5 ± 0.1	6.6 ± 0.1	108 ± 6	6.6 ± 0.1
Chi1-phe1	6.9 ± 0.1*,#	8.1 ± 0.2*,#	100	8.1 ± 0.2*,#	5.6 ± 0.0*,#	55 ± 7*,#	5.2 ± 0.1*,#
Chi2	8.7 ± 0.2	10.0 ± 0.1*	100	9.9 ± 0.1*	7.0 ± 0.1*	108 ± 6	7.0 ± 0.1*
Chi2-phe1	6.4 ± 0.1*,#	8.8 ± 0.2*,#	100	8.7 ± 0.2*,#	5.9 ± 0.0*,#	62 ± 5*,#	5.5 ± 0.1*,#
Chi3	9.5 ± 0.1*	9.9 ± 0.1*	100	9.8 ± 0.1*	7.0 ± 0.1*	105 ± 7	7.0 ± 0.1
Chi3-phe1	8.3 ± 0.1#	9.4 ± 0.2#	100	9.3 ± 0.2#	6.3 ± 0.1#	53 ± 5*,#	5.9 ± 0.1 #
Ex-ala2	9.8 ± 0.1*	10.0 ± 0.1*	100	10.0 ± 0.1*	7.3 ± 0.1*	105 ± 8	7.2 ± 0.1*
Ex-ala2-phe1	8.4 ± 0.1#	9.8 ± 0.1*	100	9.8 ± 0.1*	6.7 ± 0.1#	51 ± 5*,#	6.2 ± 0.0 #
Ex4	9.9 ± 0.1*	10.0 ± 0.1*	100	10.1 ± 0.1*	7.2 ± 0.1*	87 ± 4	7.0 ± 0.1
Ex-phe1	7.8 ± 0.1*,#	9.0 ± 0.2*,#	100	8.9 ± 0.2*,#	6.0 ± 0.2 #	12 ± 1*,#	4.6 ± 0.2*,#
GLP-1-gly2	7.2 ± 0.1*	8.8 ± 0.1*	100	8.8 ± 0.1*	5.8 ± 0.0*	101 ± 5	5.8 ± 0.0*
GLP-1-gly2-phe1	6.5 ± 0.2*,#	7.0 ± 0.2*,#	100	7.1 ± 0.2*,#	4.8 ± 0.2*,#	16 ± 1*,#	3.6 ± 0.3*,#

^aMean ± SEM signaling parameter estimates from data shown in Figure 2 and Figure S-2, n = 5 experimental repeats. Binding experiments were performed in HEK293-SNAP-GLP-1R cells, signaling experiments were performed in CHO-K1-βarr2-EA-GLP-1R cells. Signaling parameter estimates were determined from 3-parameter fitting. E_max values are expressed relative to the global maximum for full agonists in each assay. All compounds are full agonists for cAMP in this assay, so E_max was globally constrained to 100%. *p < 0.05 versus GLP-1, and #p < 0.05 for Phe1 ligand versus corresponding His1 ligand, determined by one-way ANOVA with Tukey’s test.