Proton efflux during Ca2+ uptake in a reconstituted Ca2+ pump system.
نویسندگان
چکیده
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-.
منابع مشابه
Evidence for proton countertransport by the sarcoplasmic reticulum Ca2(+)-ATPase during calcium transport in reconstituted proteoliposomes with low ionic permeability.
To ascertain the coupling between Ca2+ and H+ fluxes during Ca2+ transport by the Ca2(+)-pumping ATPase of the sarcoplasmic reticulum, we used well characterized reconstituted proteoliposomes. The method for the functional reconstitution of the Ca2(+)-ATPase was an extension of our recently published procedure (Rigaud, J. L., Paternostre, M. T., and Bluzat, A. (1988) Biochemistry, 27, 2677-2688...
متن کاملProperties of a reconstituted calcium pump.
1. The translocation of 45Ca2+ in vesicles reconstituted with purified Ca2+ ATPase of sarcoplasmic reticulum and phospholipids was dependent on ATP and varied greatly with the composition of the phospholipids. 2. In contrast to sarcoplasmic reticulum fragments, the reconstituted vesicles were impermeable to 14C-labeled oxalate, 3H- or 32P-labeled ATP, or 32P-i. There was no translocation of pho...
متن کاملFunctional reconstitution of the cardiac sarcoplasmic reticulum Ca2(+)-ATPase with phospholamban in phospholipid vesicles.
The Ca2(+)-ATPase in cardiac sarcoplasmic reticulum (SR) is under regulation by phospholamban, an oligomeric proteolipid. To determine the molecular mechanism by which phospholamban regulates the Ca2(+)-ATPase, a reconstitution system was developed, using a freeze-thaw sonication procedure. The best rates of Ca2+ uptake (700 nmol/min/mg reconstituted vesicles compared with 800 nmol/min/mg SR ve...
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The effects of the condensation product of N-methyl-p-methoxyphenethylamine with formaldehyde (compound 48/80) and ruthenium red on the partial reactions of the catalytic cycle of the sarcoplasmic reticulum Ca2+-ATPase of skeletal muscle were studied. The ATPase activity and both Ca2+ and Sr2+ uptake were inhibited by compound 48/80 when oxalate was used as a precipitating agent. The degree of ...
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Ca2+ Pump, H+-ATPase, Membrane Vesicles, Coleoptile, Zea mays Microsomal vesicles prepared from the ER and the Golgi apparatus of maize coleoptiles possess an ATP-fueled, Cl_-dependent proton pump which can cause an intravesicular acidifica tion of the vesicles (A. Hager and M. Heimle, Z. Naturforsch. 36 c, 997 (1981); A. Hager et al., Z. Naturforsch. 35 c, 783-793 (1980)). This acidification ...
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ورودعنوان ژورنال:
- The Japanese journal of physiology
دوره 36 1 شماره
صفحات -
تاریخ انتشار 1986