@article{oai:gifu-pu.repo.nii.ac.jp:00009832,
 author = {NOMOTO, HIROSHI and SHOJI, HIROKI and HAYASHI, KYOZO},
 journal = {岐阜藥科大學紀要, The annual proceedings of Gifu College of Pharmacy},
 month = {Jun},
 note = {P(論文), Nicotinic acetylcholine receptor (AChR) is a multisubunit membrane glycoprotein which functions as a ligand-triggered cation channel. Receptors from electric tissues and skeletal muscle have a molecular weight of approximately 290,000 as a monomer and are composed of four types of polypeptide chains which assemble into a heterologous α_2βγδ pentamer. We determined the carbohydrate structure of Torpedo AChR, which was the first determination for neurotransmitter receptors. About 70 % of the oligosaccharides of the AChR were of the high mannose-type, Man_9GlcNAc_2 and Man_8GlcNAc_2. These two types of oligosaccharides were distributed in all the subunits. The remaining were various kinds of complex-type oligosaccharides, existing mainly in the γ and δ subunits. The α and β subunits had only one carbohydrate chain each, while the γ and δ subunits had two and three carbohydrate chains, respectively. These glycosylation sites were identified by sequencing glycopeptides obtained by lectin-affinity chromatography. The participation of oligosaccharides in ligand-binding of AChR was examined using a newly developed binding assay. The sialic acids and high mannose-type oligosaccharides on AChR were found to be unnecessary for its ligand binding. Next we found that the β and δ subunits of Torpedo AChR were phosphorylated on their tyrosine residues. The level of the phosphorylation was enhanced by incubating the AChR-rich membrane fraction with cholinergic ligands. This suggests that cholinergic agonists physiologically regulate phosphorylation on tyrosine in vivo, which might be included in the desensitization mechanism of the receptor. We also examined the spatial relation of proteins surrounding AChR using Torpedo AChR-rich membrane fraction. Bifunctional crosslinkers revealed an intimate relation among the AChR γ subunit, 43-kD protein, and dystrophin. Finally, we found neurotoxin-binding activities in the su-pernatant fraction obtained by ultracentrifugation of a homogenate of the electric organ, which usually does not contain AChR. This new activity was different in nature from AChR, and could function as a regulator or a modulator for AChR function.},
 pages = {19--41},
 title = {<Review>Biochemical Study on Nicotinic Acetylcholine Receptor},
 volume = {43},
 year = {1994}
}