Table 2

Nanomolar affinity estimates and structure-activity relationships for drugs binding to cloned B₁ and B₂ receptors in three species for which both receptors have been cloned and sequenced

Compound	Structure		Cloned human receptors		Cloned rabbit receptors		Cloned mouse receptors
Compound	−4	−3	−2	−1	0	1	2	3	4	5	6	7	8	9	B₁R^2-a	B₂R^2-b	B₁R^2-c	B₂R^2-d	B₁R^2-e	B₂R^2-f
Native kinins (B₂R agonists)
BK						Arg	Pro	Pro	Gly	Phe	Ser	Pro	Phe	Arg	2000	0.54	>5000	4.5	200^2-g	0.48
Lys-BK					Lys	Arg	Pro	Pro	Gly	Phe	Ser	Pro	Phe	Arg	42	0.63	19	2	510	0.52
Met-Lys-BK				Met	Lys	Arg	Pro	Pro	Gly	Phe	Ser	Pro	Phe	Arg	70	2.1	16			3.6
B₁R agonists
des-Arg⁹-BK						Arg	Pro	Pro	Gly	Phe	Ser	Pro	Phe		720	8100	32	>1000	0.7	8.1
Lys-des-Arg⁹-BK					Lys	Arg	Pro	Pro	Gly	Phe	Ser	Pro	Phe		0.2	>30000	0.23	>1000	1.7	6400
Sar-[d-Phe⁸]des-Arg⁹-BK					Sar^2-h	Arg	Pro	Pro	Gly	Phe	Ser	Pro	d-Phe				68^2-i
Tyr-Gly-Lys-Aca-Lys-des-Arg⁹-BK	Tyr	Gly	Lys	Aca	Lys	Arg	Pro	Pro	Gly	Phe	Ser	Pro	Phe				0.2^2-j
Peptide B₂R antagonist
Hoe 140					d-Arg	Arg	Pro	Hyp	Gly	Thi	Ser	d-Tic	Oic	Arg	>10000	0.41	>5000	2	>10000	0.23
NPC 17731					d-Arg	Arg	Pro	Hyp	Gly	Phe	Ser	X^2-k	Oic	Arg	126^2-l	0.18^2-m
B₁R antagonists
[Leu⁸]des-Arg⁹-BK						Arg	Pro	Pro	Gly	Phe	Ser	Pro	Leu		440	>30000	80		4.1	>30000
Lys-[Leu⁸]des-Arg⁹-BK					Lys	Arg	Pro	Pro	Gly	Phe	Ser	Pro	Leu		1.3	>30000	0.43	>100	7.5	>30000
Ac-Lys-[MeAla⁶, Leu⁸]des-Arg⁹-BK					Ac-Lys	Arg	Pro	Pro	Gly	Phe	Me-Ala	Pro	Leu		670^2-n	>10000^2-n			>5000^2-n	>10000^2-n
R-715					Ac-Lys	Arg	Pro	Pro	Gly	Phe	Ser	βD-Nal	Ile		0.66^2-n	>10000^2-n			41^2-n	>10000^2-n
Mixed B₁ and B₂R antagonists
Hoe 140-des-Arg					d-Arg	Arg	Pro	Hyp	Gly	Thi	Ser	d-Tic	Oic		60		27		24
NPC 18565					d-Arg	Arg	Pro	Hyp	Gly	Phe	Ser	X^2-k	Oic		0.07^2-l	26.1^2-o
B9858				Lys	Lys	Arg	Pro	Hyp	Gly	Igl	Ser	d-Igl	Oic		0.04^2-n	146^2-n			5.4^2-n	44^2-n
B9430					d-Arg	Arg	Pro	Hyp	Gly	Igl	Ser	d-Igl	Oic	Arg	12.6^2-p	0.25^2-p			248^2-n	0.33^2-n
Nonpeptide B₂R antagonists
WIN 64338	[[4-[[2-[[bis(cyclohexylamino)methylene]amino]-3-(2-naphthyl)-1-oxopropyl]amino]phenyl]methyl]tributylphosphonium chloride monohydrochloride			64^2-q		150
FR 173657	8-[3-[N-[(E)-3-(6-acetamidopyridin-3-yl)acryloylglycyl]-N-methylamino]-2,6-dichlorobenzyloxy]-2-methylquinoline		>10000^2-r	8.9^2-r

↵2-a Nanomolar affinity estimates are IC₅₀ values from binding competition with 1 nM [³H]Lys-des-Arg⁹-BK to transiently expressed human B₁R in COS-7 cells. From Menke et al. (1994), except if otherwise indicated. Other comparative estimates based on cloned human B₁Rs are found elsewhere (Bastian et al., 1997; Aramori et al., 1997; Austin et al., 1997).
↵2-b Nanomolar affinity estimates are IC₅₀ values from binding competition with 100 pM [³H]BK to stably expressed human B₂R in CHO cells. From Hess et al. (1994), except if otherwise indicated. Other comparative estimates are found elsewhere (Aramori et al., 1997).
↵2-c Nanomolar affinity estimates are IC₅₀ values from binding competition with 0.5 nM [³H]Lys-[Leu⁸]des-Arg⁹-BK to transiently expressed rabbit B₁R in COS-7 cells. From MacNeil et al. (1995), except if otherwise indicated.
↵2-d Nanomolar affinity estimates are IC₅₀ values from binding competition with 1 nM [³H]BK to transiently expressed rabbit B₂R in COS-1 cells (Bachvarov et al., 1995).
↵2-e Nanomolar affinity estimates are K_i values from binding competition with [³H]Lys-des-Arg⁹-BK to transiently expressed murine B₁R in COS cells. From Hesset al. (1996), except if otherwise indicated. Other comparative estimates are found elsewhere (Pesquero et al., 1996).
↵2-f Nanomolar affinity estimates are IC₅₀ values from binding competition with 100 pM [³H]BK to transiently expressed murine B₂R in COS cells (Hess et al., 1994).
↵2-g Pesquero et al. (1996) also report an IC₅₀ of about 200 nM, but the value is much higher (>1 μM) if the assay is run in the presence of the kininase I inhibitor mergepta, suggesting that the formation of des-Arg⁹-BK may distort the estimate.
↵2-h Abbreviations: Ac, N-acetyl; Aca, ε-aminocaproic acid; Hyp, 4-hydroxy-l-proline; Igl, α-(2-indanyl)glycine; β-Nal: β-2-naphthylalanine; Oic, octahydroindole-2-carboxylic acid; Thi, β-2-thienylalanine; Tic, 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid; Sar, sarcosine (N-methyl-glycine).
↵2-i Nanomolar IC₅₀ value from the binding competition of 1 nM [¹²⁵I]Tyr-Gly-Lys-Aca-Lys-des-Arg⁹-BK to wild type rabbit B₁R in cultured aortic SMCs (Levesque et al., 1995a).
↵2-j K_D value for the iodinated form of the peptide in a saturation binding assay to wild type rabbit B₁R in cultured aortic SMCs; (Levesque et al., 1995a).
↵2-k X = D-HypEtrans-propyl.
↵2-l Nanomolar K_i value from the binding competition of 1 nM [³H]Lys-des-Arg⁹-BK to transiently expressed human B₁R in HEK 293 cells (Leeb et al., 1997).
↵2-m Nanomolar K_D value for binding of [³H]NPC 17731 to transiently expressed human B₂R in HEK 293 cells (Leebet al., 1997).
↵2-n Data from MacNeil et al. (1997). K_ivalues derived from human B₂R stably transfected in CHO cells, or human or murine B₁R or murine B₂R transiently transfected in COS cells.
↵2-o Nanomolar K_i value from the binding competition of 1 nM [³H]NPC 17731 to transiently expressed human B₂R in HEK 293 cells (Leeb et al., 1997).
↵2-p Nanomolar IC₅₀ value from the binding competition of 0.5 nM [³H]Lys-des-Arg⁹-BK to wild type human B₁R in IMR-90 cells or of 0.3 nM [³H]BK to stably expressed human B₂R in CHO cells. (Gera et al., 1996; Stewart et al., 1996).
↵2-q K_i value from binding competition with 1–2 nM [³H]BK to wild type human B₂R in IMR-90 cells (Sawutzet al., 1994).
↵2-r Nanomolar affinity estimates are IC₅₀ values from binding competition with 500 pM of either [³H]Lys-des-Arg⁹-BK (B₁R) or [³H]BK (B₂R) to stably expressed human receptors in CHO cells (Aramoriet al., 1997).