Influence of EDTA on the ATPase activities of plasma membranes from winter wheat roots.

Plasma membrane vesicles were purified from roots of winter wheat seedlings (Triticum aestivum L. cv. Marton-vásári-8) by aqueous polymer two-phase partitioning. The ATPase activity of vesicles in the presence of Ca was independent of but in the presence of Mg depended on the EDTA concentration in the ATPase assay. The potassium stimulation and vanadate inhibition of the MgATPase also depended on the EDTA concentration. Consequences of these results are briefly discussed.