Photoaffinity labeling of the beta-adrenergic receptor.

Journal Article

A new photoactive beta-adrenergic antagonist, p-azidobenzylcarazolol (pABC) has been synthesized by combining a carbazole moiety with a p-azido-benzyl substituent. The compound has been labeled with tritium to a specific activity of 26 Ci/mmol. In frog erythrocyte membranes, [3H]p-azido-benzylcarazolol binds to the beta-adrenergic receptor with the expected beta 2 specificity and with high affinity (KD congruent to 100 +/- 10 pM). Unlabeled p-azido-benzylcarazolol can irreversibly inactivate the [3H]dihydroalprenolol-binding activity of frog erythrocyte membranes in a photodependent manner which can be prevented by beta-adrenergic agents. Incubation of frog erythrocyte membranes or digitonin-solubilized preparations of these membranes or digitonin-solubilized preparations of these membranes which had been enriched in beta-adrenergic receptors by a Sepharose-alprenolol chromatography step led to covalent incorporation of radioactivity into a Mr = 58,000 peptide. Specific incorporation of [3H]pABC into the Mr = 58,000 peptide could be prevented by both beta-adrenergic agonists and antagonists. This peptide has previously been purified and shown to contain the beta-adrenergic receptor-binding site (Shorr, R. G. L., Lefkowitz, R. J., and Caron, M. G. (1981) J. Biol. Chem. 256, 5820-5826). Thus, photoaffinity labeling of the beta-adrenergic receptor protein directly identifies the same hormone-binding subunit as has been isolated by conventional purification techniques.

Full Text

Duke Authors

Cited Authors

  • Lavin, TN; Heald, SL; Jeffs, PW; Shorr, RG; Lefkowitz, RJ; Caron, MG

Published Date

  • November 25, 1981

Published In

Volume / Issue

  • 256 / 22

Start / End Page

  • 11944 - 11950

PubMed ID

  • 6271767

International Standard Serial Number (ISSN)

  • 0021-9258

Language

  • eng

Conference Location

  • United States