Open AccessATP-dependent Ca 2+ uptake into plant membrane vesicles
Author(s) -
Joachim Groß,
Dieter Marmé
Publication year - 1978
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.75.3.1232
Subject(s) - vesicle , oligomycin , oxalate , valinomycin , chemistry , efflux , biophysics , membrane , plant cell , biochemistry , biology , atpase , inorganic chemistry , enzyme , gene
Membrane vesicles were extracted from etiolated and light-grown plants, a plant cell suspension culture, and an alga. Upon addition of ATP and Mg2+ , active Ca2+ uptake into the vesicles against a concentration gradient was shown. The dependence of this uptake on ATP and Mg2+ concentrations, pH, and temperature is described. In the absence of oxalate, equilibrium between Ca2+ uptake and efflux was reached after about 30 min. In the presence of oxalate, Ca2+ accumulation continued for at least 120 min. Ca2+ efflux from preloaded vesicles did not depend on ATP. Addition of the ionophores A23187 and Ro 20-0006/006 caused an immediate release of accumulated free Ca2+ . ATP-dependent Ca2+ uptake was not inhibited by 10 μM oligomycin.