Subunit composition of bovine muscle acetylcholine receptor.

Acetylcholine receptors from fetal calf muscle were purified to homogeneity (specific activity up to 7500 nmol/g of protein), in reasonable yields (20-50%), and near-milligram quantity. Purification was by affinity chromatography on Naja naja siamensis toxin coupled to agarose by using methods similar to those for receptors from fish electric organs, but with modifications to account for the low concentration of receptor in muscle and the high probability of proteolysis. Immunochemical methods are described for approximating the extent of proteolysis in receptor preparations.

Mapping of surface structures of electrophorus acetylcholine receptor using monoclonal antibodies.

Forty monoclonal antibodies to acetylcholine receptor from the electric organs of Electrophorus electricus have been characterized by immunoglobulin isotype, affinity for receptor, and specificity for species, subunit, and determinants within subunits. Using these antibodies, nine immunogenic regions on the receptor molecule were distinguished. Most of these are species specific, and are located on various subunits of the acetylcholine receptor.

Purification of acetylcholine receptors, reconstitution into lipid vesicles, and study of agonist-induced cation channel regulation.

We report the purification of acetylcholine receptors with active agonist-regulated cation channels from Torpedo californica electric organ tissue by five methods. In one method, previously used by others, contaminating proteins were removed from partially purified membranes by alkaline extraction, preserving membrane integrity throughout the procedure. In the other four methods, acetylcholine receptors were purified after solubalization with sodium cholate.