title: Affinity alkylation labels two subunits of the reduced acetylcholine receptor from mammalian muscle.
abstract: The acetylcholine receptor from denervated rat skeletal muscle was purified by affinity chromatography and, after reduction, was treated with the affinity alkylating agent 4-(N-maleimido)benzyltri[3H]methylammonium iodide. The receptor specifically incorporated approximately 1 mol of alkylating agent per mol of 125I-labeled alpha-bungarotoxin bound. Analysis of the labeled receptor by polyacrylamide gel electrophoresis in sodium dodecyl sulfate showed that two subunits were labeled; their apparent molecular weights were 45,000 and 49,000. These results suggest that the affinity reagent labels a second site for acetylcholine binding in the muscle receptor that is not labeled in receptors from Electrophorus or Torpedo.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000477:Alkylating Agents; D000478:Alkylation; D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism; D002846:Chromatography, Affinity; D005399:Fishes; D066298:In Vitro Techniques; D008970:Molecular Weight; D009121:Muscle Denervation; D009132:Muscles / Q000032:analysis*; D000644:Quaternary Ammonium Compounds; D051381:Rats; D011950:Receptors, Cholinergic / Q000032:analysis*
chemical_list: D000477:Alkylating Agents; D002038:Bungarotoxins; D000644:Quaternary Ammonium Compounds; D011950:Receptors, Cholinergic; D000109:Acetylcholine
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