ABSTRACT
Electric activity of fragmented sarcoplasmic reticulum (FSR) in the model system organic phase-water was investigated by dynamic capacity method. FSR induced Mg-ATP, Ca2+-dependent change of border volt-potential only when phospholipids were present in the organic phase. It is suggested that FSR electric activity at the interface lipid-water is conditioned by functioning Ca2+, Mg2+-ATPase.
Subject(s)
Ca(2+) Mg(2+)-ATPase/metabolism , Calcium-Transporting ATPases/metabolism , Ion Channels/metabolism , Membrane Proteins/metabolism , Sarcoplasmic Reticulum/physiology , Animals , Calcium/metabolism , In Vitro Techniques , Membrane Potentials , Models, Biological , Phosphatidylcholines , Phospholipids , Rabbits , Sarcoplasmic Reticulum/enzymology , WaterABSTRACT
Conditions are experimentally found for association of liposomes formed of asolectine and Ca2+-ATPase of sarcoplasmic reticulum with interface "asolectine solution in decane--water". It is established that Ca2+ ions participate in the change of Mg-ATP-dependent interface potential in this model system.
Subject(s)
Calcium-Transporting ATPases/analysis , Liposomes/analysis , Proteolipids/analysis , Animals , Membrane Potentials , Muscles/enzymology , Rabbits , SolubilityABSTRACT
Transport of Ca2+ to vesicles of the sarcoplasmic reticulum and its subsequent removal by AMP is accompanied by fluorescence intensification and quenching, respectively, of the charged potentially-dependent probes of 1-anilino-8-naphthalenesulphonate and 3,3'-dipropilthiodicarbocyanin as well as 4-dimethylaminochalcone responding to conformation changes in membranes. The transmembrane electrophoretic distribution of synthetic fat-soluble ions of phenyldicarboundecaborane and tetraphenylphosphonium during Ca2+ accumulation is characterized by uptake of phenyldicarboundecaborane with the subsequent removal by protonophore of m-cholorocarbonylcyanide phenylhydrazone or AMP; the uptake of tetraphenylphosphonium is absent. This testifies to the fact that the Ca2+ transport in vesicles is accompanied by the formation of a membrane potential with a positive sign inside the vesicles.