Biochemical regulation of sarcoplasmic reticulum Cl- channel from human atrial myocytes: involvement of phospholamban.

Sarcoplasmic reticulum (SR) membrane vesicles derived from human atrium were characterized by specific ryanodine binding assay and fused into planar lipid bilayers. The tritiated form of the alkaloid bound to its receptor with a K(D) of 2.2 nM and a Bmax of 268 fmol/mg protein respectively.