Characterization of histamine H/sub 1/-receptor binding peptides in guinea pig brain using (/sup 125/I)iodoazidophenpyramine, an irreversible specific photoaffinity probe
Aminophenpyramine, a derivative of mepyramine (pyrilamine), a typical antagonists of histamine at its H/sub 1/ receptor was synthesized and converted into (/sup 125/I)iodoazidophenpyramine, a potential photoaffinity probe for the H/sub 1/ receptor. In the dark, reversible binding of this probe to cerebellar membranes occurred with a K/sub d/ of 1.2 x 10/sup -11/ M and a B/sub max/ of 240 fmol/mg of protein and was inhibited by various H/sub 1/-receptor antagonists with the expected potencies. These features establish the compound as one of the most potent H/sub 1/-receptor antagonists known so far. Upon IV irradiation, 5% of the bound radioactivity was covalently incorporated into cerebellar membrane polypeptides as shown by standard NaDodSO/sub 4//PAGE. Two bands of 47 and 56 kDa were consistently labeled, labeling being prevented by various H/sub 1/-receptor antagonists with the expected potencies and stereoselectivity. In the presence of protease inhibitors, labeling of the 56-kDa peptide increased at the expense of the 47-kDa peptide, suggesting that the latter was produced by hydrolysis of the former under the action of membrane proteases. In the absence of 2-mercaptoethanol, a band of 350-400 kDa appeared, apparently at the expense of the lighter bands, suggesting that the latter might be linked by one or more disulfide bridges to a higher molecular mass complex. The authors propose that at least part of the ligand binding domain of the histamine H/sub 1/ receptor resides within a subunit of apparent molecular mass 56,000.
- Research Organization:
- Institut National de la Sante et de la Recherche Medicale, Paris (France)
- OSTI ID:
- 6244909
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 85:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CELL MEMBRANES
BIOCHEMICAL REACTION KINETICS
HISTAMINE
LABELLED COMPOUNDS
CHEMICAL PREPARATION
RECEPTORS
MOLECULAR STRUCTURE
ANTIHISTAMINICS
AZIDO COMPOUNDS
BRAIN
CEREBELLUM
DERIVATIZATION
DOSE-RESPONSE RELATIONSHIPS
ENZYME INHIBITORS
IODINE 125
PEPTIDE HYDROLASES
PEPTIDES
SWINE
AMINES
ANIMALS
AZOLES
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
HETEROCYCLIC COMPOUNDS
HYDROLASES
IMIDAZOLES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques