title: A Ca++-dependent and -selective ionophore as part of the Ca++ plus Mg++-dependent adenosinetriphosphatase of sarcoplasmic reticulum.
abstract: Solubilized Ca(++) + Mg(++)-dependent adenosinetriphosphatase (EC 3.6.1.3; ATP diphosphohydrolase) from sarcoplasmic reticulum increased bimolecular lipid membrane (oxidized cholesterol) conductance several hundred-fold. The relative conductance change and the relative permeability elicited by this material has the following sequence: Ba(++) > Ca(++) > Sr(++) > Mg(++) > Mn(++) > Zn(++), Na(+), K(+), Cs(+), Li(+), and Rb(+). Zn(++) and Na(+) strongly inhibit the increase in Ca(++) conductance obtained with solubilized Ca(++) + Mg(++)-dependent adenosinetriphosphatase. The Ca(++)-ionophore is an integral part of the Ca(++) + Mg(++)-dependent adenosinetriphosphatase enzyme and may function as a Ca(++)-carrier in the overall Ca(++)-pump of sarcoplasmic reticulum.
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001464:Barium / Q000378:metabolism; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002586:Cesium / Q000378:metabolism; D008094:Lithium / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D008567:Membranes, Artificial; D009132:Muscles / Q000648:ultrastructure; D010539:Permeability; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012413:Rubidium / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology; D013324:Strontium / Q000378:metabolism; D013997:Time Factors; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology
chemical_list: D008567:Membranes, Artificial; D002586:Cesium; D001464:Barium; D008345:Manganese; D008094:Lithium; D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D015032:Zinc; D012413:Rubidium; D011188:Potassium; D002118:Calcium; D013324:Strontium