VANADIUM INHIBITION OF HUMAN PARIETAL LOBE ATPASES

In vitro influence of vanadate and vanadyl ions on the activities of N a,K- and Ca,Mg-ATPase from synaptosomal membranes of the parietal lobe of the human brain were compared. 1. Vanadate and vanadyl inhibit the enzymes activities in the investigated fraction. 2. Vanadate is a mor e effective inhibitor of both ATPases in the concentrations above 50 m u M and vanadyl is an effective inhibitor in a very low concentration (10 nM). 3. Vanadate seems to be an uncompetitive inhibitor of Na,K-AT Pase (K-i = 880 nM).