Time-dependent inhibition of Na+/K+-ATPase induced by single and simultaneous exposure to lead and cadmium

Time-dependent interactions of Na + /K + -ATPase, isolated from rat brain synaptic plasma membranes (SPMs), with Cd 2+ and Pb 2+ ions in a single exposure and in a mixture were investigated in vitro. The interference of the enzyme with these metal ions was studied as a function of different protein concentrations and exposure time. The aim of the work was to investigate the possibility of selective recognition of Cd 2+ and Pb 2+ ions in a mixture, on the basis of the different rates of their protein-ligand interactions. Decreasing protein concentration increased the sensitivity of Na + /K + -ATPase toward both metals. The selectivity in protein-ligand interactions was obtained by variation of preincubation time (incubation before starting the enzymatic reaction).