Biochemical characterization of the Ca2+ release channel of skeletal and cardiac sarcoplasmic reticulum

Abstract
Rapid mixing-vesicle ion flux and planar lipid bilayer-single channel measurements have shown that a high-conductance, ligand-gated Ca2+ release channel is present in ‘heavy’, junctional-derived membrane fractions of skeletal and cardiac muscle sarcoplasmic reticulum. Using the release channel-specific probe, ryanodine, a 30S protein complex composed of polypeptides of Mr ∼ 400 000 has been isolated from cardiac and skeletal muscle. Reconstitution of the complex into planar lipid bilayers has revealed a Ca2+ conductance with properties characteristic of the native Ca2+ release channel.