Table 2.

Affinities of hGRPR point mutants in Group II for [D-Tyr⁶, β-Ala¹¹, Phe¹³, Nle¹⁴]Bn(6-14) [Univ.Lig]

	LOCATION	POINT MUTATION	Univ.Lig Affinity (nM ± SEM)
	Wild type hGRPR 0.1×106	-	0.10 ± 0.01
42	EC2	L102A	0.069 ± 0.003
43		W106A	0.083 ± 0.006
44		L107A	0.17 ± 0.02*
45		F108A	0.14 ± 0.01
46		G109A	0.050 ± 0.002
47		K114A	0.15 ± 0.01*
48	EC3	F178A	0.060 ± 0.032
49		S211A	0.11 ± 0.01
50	EC4	S288T	0.12 ± 0.02
51		V294L	0.17 ± 0.01*
52		S297T	0.091 ± 0.001
53		S297A	0.18 ± 0.02*
54		F301A	0.17 ± 0.01*

Group II (n=13) comprise point mutants made in a hGRPR amino acids which are present in all BnR’s with high affinity for [D-Tyr⁶, β-Ala¹¹, Phe¹³, Nle¹⁴]Bn(6-14) [Univ.Lig] and in also in a similar position in hCCK_AR, which has low affinity for [D-Tyr6, β-Ala11, Phe13, Nle¹⁴]Bn(6-14) [Univ.Lig] identified as described in Methods. Experiments were performed as described in Table 1 and Fig. 1 legend. The affinities (IC₅₀) were calculated as described in Methods. Values are means ± SEM from three experiments for those mutants showing no affinity change and 4 to 6 experiments for any showing differences from control and in each experiment each point was measured in duplicate.

^*(in bold)=p<0.05 compared to wild type hGRPR expressed at similar expression levels.