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Glycoprotein nature of α 2 ‐adrenergic receptors labeled with p ‐azido[ 3 H] clonidine in calf retina membranes
Author(s) -
Convents André,
De Backer Jean-Paul,
Van Driessche Edilbert,
Convents Daniel,
Beeckmans Sonia,
Vauquelin Georges
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80142-x
Subject(s) - receptor , chemistry , agonist , endoglycosidase h , membrane , lectin , glycoprotein , neuraminidase , biochemistry , photoaffinity labeling , sialic acid , gel electrophoresis , adrenergic receptor , biophysics , biology , enzyme , endoplasmic reticulum , golgi apparatus
α 2 ,‐Adrenergic receptors in calf retina membranes can be specifically labeled with the tritiated agonist p ‐azido[ 3 H]clonidine. Saturation binding in the dark occurs with high affinity (1.3 ± 0.3 nM) to a single class of sites (1122 ± 67 fmol/mg protein). Irradiation of the membrane‐bound radioligand results in the labeling of a peptide band with an apparent size of 65 kDa and a characteristic pharmacological profile for an α 2 ‐adrenergic receptor. The carbohydrate moieties of the α 2 ‐receptor are characterized by lectin affinity chromatography and glycosidase treatment. The Nonidet P‐40‐solubilized, p ‐azido[ 3 H]clonidine‐labeled receptors are completely retained by Con A‐ as well as WGA‐Sepharose columns. Neuraminidase, α‐mannosidase and TFMS do not affect the electrophoretic mobility of the receptor on SDS‐PAGE whereas endoglycosidase F reduces the apparent size to 45 kDa.