Two bradykinin binding sites with picomolar affinities

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

Research output: Contribution to journalArticlepeer-review

109 Scopus citations


Bradykinin(BK) and related peptides exert a wide range of effects on several organ systems. We have attempted to sort out these effects by using the binding interaction of [3H]BK at the membrane levels with in vitro receptor binding techniques. High specific activity [3H]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 (K(d)) for [3H]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 K(d) of 910 pM, a maximum number of bindig 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 [3H]BK in the guinea-pig ileum is inhibited by physiological concentrations of monovalent and divalent cations.

Original languageEnglish (US)
Pages (from-to)504-512
Number of pages9
JournalJournal of Pharmacology and Experimental Therapeutics
Issue number2
StatePublished - 1986

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology


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