Characterization of Torpedo californica Acetylcholine Receptor: Its Subunit Composition and Ligand-binding Properties

The initial observation of the specificity of in vivo blockade of the nicotinic acetylcholine receptor (AChR) by neurotoxins from Bungarus multicinctus α-toxin (α-BGT) and similar toxins from Naja species (Lee and Chang 1966; Lee et al. 1967) afforded unique tools for the characterization of these receptors at the biochemical level. Quantities of AChR suitable for such types of study are available only from the electric tissues of Electrophorus electricus, Torpedo and Narcine species. In vitro studies are carried out at the present time with two types of preparations: (1) highly enriched membrane fragments from Torpedo marmorata (Cohen et al. 1972) or from Torpedo californica (Duguid and Raftery 1973; Reed et al. 1975) and (2) detergent-solubilized, purified AChR.