Two bradykinin binding sites with picomolar affinities

Journal Article · Thu May 01 00:00:00 EDT 1986 · J. Pharmacol. Exp. Ther.; (United States)

OSTI ID:5429920

Manning, D C; Vavrek, R; Stewart, J M; Snyder, S H

Bradykinin (BK) and related peptides exert a wide range of effects on several organ systems. We have attempted to sort out these effects by studying the binding interaction of (/sup 3/H)BK at the membrane level with in vitro receptor binding techniques. High specific activity (/sup 3/H)BK and an enzyme inhibitor cocktail has enabled us to label two BK binding sites with different affinity and peptide specificity in several guinea-pig tissues. In the guinea-pig ileum the high-affinity site has an equilibrium dissociation constant (Kd) for (/sup 3/H)BK of 13 pM and a maximal number of binding sites of 8.3 pmol/g of tissue wet weight. The low-affinity guinea-pig ileum site displays a Kd of 910 pM, a maximum number of binding sites of 14 pmol/g of tissue wet weight and shows a greater selectivity for BK analogs over Lysyl-BK analogs. Two similar sites can also be discriminated in kidney and heart. The potencies of a series of BK analogs at the high-affinity guinea-pig ileum site correlate well with their potencies in contracting ileal smooth muscle. The binding of (/sup 3/H)BK in the guinea-pig ileum is inhibited by physiological concentrations of monovalent and divalent cations.

• Research Organization: Johns Hopkins Univ., Baltimore, MD
• OSTI ID: 5429920
• Journal Information: J. Pharmacol. Exp. Ther.; (United States), Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BRADYKININ
RECEPTORS
BIOCHEMICAL REACTION KINETICS
CATIONS
GUINEA PIGS
HEART
IN VITRO
KIDNEYS
SMALL INTESTINE
TRITIUM COMPOUNDS
VALENCE
ANIMALS
BODY
CARDIOVASCULAR SYSTEM
CHARGED PARTICLES
DIGESTIVE SYSTEM
GASTROINTESTINAL TRACT
INTESTINES
IONS
KINETICS
KININS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYPEPTIDES
PROTEINS
REACTION KINETICS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques