Table 3.

Competitive Binding of Linked NDP-α-MSH and MSH(4) Ligands to hMC4R

compound	monomer/dimer	linkera	IC50	nb	fold increase
NDP-α-MSH		none	5.6 ± 0.2 nM	3
9	D	Ph	3.5 ± 2.2 nM	4	1.4
12	M	Ph	5.0 ± 1.2 nM	4
10	D	BP	5.6 ± 3.5 nM	5	0.9
13	M	BP	5.2 ± 5.2 nM	5
11	D	TP	8.4 ± 2.9 nM	5	2.0
14	M	TP	16.5 ± 14.7 nM	5
32	D	PN	3.7 ± 0.9 nM	5	1.1
33	M	PN	3.9 ± 1.2 nM	4
MSH(4)		none	2.1 ± 0.8 μM	3
37	D	Ph	0.1 ± 0.05 μM	4	22.9
41	M	Ph	1.8 ± 0.2 μM	4
38	D	BP	0.6 ± 0.2 μM	4	4.8
42	M	BP	2.8 ± 1.1 μM	4
39	D	TP	2.6 ± 1.0 μM	4	1.9
43	M	TP	5.0 ± 3.6 μM	5
40	D	PN	0.5 ± 0.2 μM	4	3.2
44	M	PN	1.5 ± 0.7 μM	4

^aPh = phenyl linker 1; BP = biphenyl linker 2; TP = terphenyl linker 3; and PN = phenylnaphthyl linker 4.

^bThe IC₅₀ value given is the average of n independent binding experiments, each done in quadruplicate.