CHARACTERIZATION OF A RYANODINE RECEPTOR IN PERIPLANETA AMERICANA

AbstractSpecific binding sites for the alkaloid ryanodine were characterized in membrane preparations from sarcoplasmatic reticulum of Periplaneta americana skeletal muscle. Binding of [3H]ryanodine was optimal at pH 8 and at CaCl2 concentration of about 300 μmol l-1. The Ca-chelating agents EGTA (100 μmol l-1) and EDTA (100 μmol l-1) abolished 95 % and 90 % of the [3H]ryanodine binding respectively. Preincubation with Ca2+ (100 μmol l-1) restored the ryanodine binding in presence of up to 300 μmol l-1 EGTA. Radioligand binding experiments showed one class of high affinity binding sites for ryanodine. Determination of rate constants revealed 7.05 × 106 l mol-1 min-1 for associating and 3.77 × 10-3 min-1 for the dissociating [3H]ryandine ryanodine receptor complex. Solubility of the ryanodine receptor was examined with different anionic, non-ionic and zwitterionic detergents. Best solubilization results of “calcium release channel” of cockroach muscle membrane preparations were obtained with the detergent ...