Proton efflux during Ca2+ uptake in a reconstituted Ca2+ pump system.
Ca2+-pump of sarcoplasmic reticulum was partially purified and solubilized with Triton-X100 in the presence of excess phospholipids. Vesicles were reconstituted by removal of Triton with Amberlite XAD-2 and the subsequent freeze-thaw/sonication method (Kasahara, M. and Hinkle, P. C. (1977) J. Biol. Chem., 252: 7384-7390). In the reconstituted system, H+ was ejected during Ca2+ uptake and in the initial Ca2+ uptake, the molar ratio of ejected H+ to Ca2+ was found to be about 1 in the presence of a permeant anion, SCN-.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000502:physiology; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials; D011522:Protons; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000502:physiology*
D007473:Ion Channels; D011522:Protons; D000252:Calcium-Transporting ATPases; D002118:Calcium