Photoaffinity labeling of mammalian. cap alpha. /sub 1/-adrenergic receptors: identification of the ligand binding subunit with a high affinity radioiodinated probe. [Rats, guinea pigs, rabbits]

Journal Article · Wed Feb 01 04:00:00 EST 1984 · J. Biol. Chem.; (United States)

OSTI ID:6196217

Leeb-Lundberg, L M.F.; Dickinson, K E.J.; Heald, S L; Wikberg, J E.S.; Hagen, P O; DeBernardis, J F; Winn, M; Arendsen, D L; Lefkowitz, R J; Caron, M G

A description is given of the synthesised and characterization of a novel high affinity radioiodinated ..cap alpha../sub 1/-adrenergic receptor photoaffinity probe, 4-amino-6,7-dimethoxy-2-(4-(5-(4-azido-3-(/sup 125/I)iodophenyl)pentanoyl)-1-piperazinyl) quinazoline. In the absence of light, this ligand binds with high affinity (K/sub d/ = 130 pm) in a reverisble and saturable manner to sites in rat hepatic plasma membranes. The binding is stereoselective and competitively inhibited by adrenergic agonists and antagonists with an ..cap alpha../sub 1/-adrenergic specificity. Upon photolysis, this ligand incorporates irreversibly into plasma membranes prepared from several mammalian tissues including rat liver, rat, guinea pig, and rabbit spleen, rabbit lung, and rabbit aorta vascular smooth muscle cells, also with typical ..cap alpha../sub 1/-adrenergic specificity. Autoradiograms of such membrane samples subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveal a major specifically labeled polypeptide at M/sub 4/ = 78,000-85,000, depending on the tissue used, in addition to some lower molecular weight peptides. Protease inhibitors, in particular EDTA, a metalloprotease inhibitor, dramatically increases the predominance of the M/sub r/ = 78,000-85,000 polypeptide while attenuating the labeling of the lower molecular weight bands. This new high affinity radioiodinated photoaffinity probe should be of great value for the molecular characterization of the ..cap alpha../sub 1/-adrenergic receptor.

• Research Organization: Duke Univ. Medical Center, Durham, NC
• OSTI ID: 6196217
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 259:4; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
AMINES
AROMATICS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMISTRY
CATECHOLAMINES
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL BONDS
CHEMICAL REACTIONS
CHEMISTRY
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
LABELLING
LIGANDS
MEMBRANES
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PHENOLS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POLYPHENOLS
RADIOISOTOPES
RADIORECEPTOR ASSAY
RECEPTORS
TRACER TECHNIQUES