Solubilization of [3H]leukotriene D4 receptor complex from guinea pig lung membranes

Guinea pig lung membrane leukotriene D4 (LTD4) receptors were prelabeled with [3H]LTD4 and solubilized using digitonin, 3-[(3-cholamidopropyl)- dimethylammonio]-1-propane sulfonate, and other non-ionic, zwitterionic, and ionic detergents. [3H]LTD4 remains tightly associated with the receptor complex in the digitonin solubilized state. The dissociation rate of [3]LTD4 from the soluble receptor complex was increased in the presence of guanine nucleotides and sodium ions in a manner similar to that observed for the receptors in the membrane-bound state. The soluble [3H]LTD4 receptor complex was retained on wheat germ lectin affinity columns and destabilized by heat (40 +/- 4 degrees), trypsin, and chymotrypsin treatment, suggesting that the receptor is a glycoprotein. Size exclusion high pressure liquid chromatography of the soluble receptor complex showed that an apparent molecular weight of the soluble receptor complex, in the presence of digitonin, is in the range of 240,000-500,000. An approximately 20-fold enrichment of receptor-radioligand complex was achieved by passing the solubilized LTD4 receptor preparation successively through size exclusion and wheat germ lectin chromatography columns. These data provide the first step toward the purification and chemical characterization of LTD4 receptors.