Rapid breakdown of diphosphoinositide and triphosphoinositide in erythrocyte membranes.
Incubation of rabbit erythrocytes with 32Pi resulted in labeling of membrane diphosphoinositide, triphosphoinositide, and phosphatidic acid. Hypotonic lysis at 37 degress C resulted in an extremely rapid breakdown of the labeled polyphosphoinositides. This breakdown could be retarded by lysis in the presence of EDTA and by lowering the temperature to 0 degrees thus allowing preparation of membranes with minimum breakdown of the labeled lipids. Rapid breakdown of di- and triphosphoinositide in isolated membranes could be initiated by Ca++ or to a lesser extent by Mg++ and prevented by detergents and by heating to 75 degrees C. Assay of radiolabeled lipid was carried out by a method which bypassed prior lipid extraction and which enabled sequential sampling of reactions at 10-second intervals. This method was more convenient than standard procedures and gave yields of di- and triphosphoinositide equivalent to that obtained by the method of Folch.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D004912:Erythrocytes / Q000378:metabolism*; D006461:Hemolysis; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D010712:Phosphatidic Acids / Q000378:metabolism; D010716:Phosphatidylinositols / Q000378:metabolism*; D011136:Polysorbates / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011817:Rabbits; D012964:Sodium / Q000494:pharmacology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology
D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; D011136:Polysorbates; D012967:Sodium Dodecyl Sulfate; D004492:Edetic Acid; D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium