[Effect of fluoroaluminate on the ATP-hydrolysing and Ca2+-transporting activity of the purified Ca2+, Mg2+-ATPase of myometrium cell plasma membranes].

Fluoroaluminate, known modulator of G-proteins, inhibits ATP-hydrolase activity of purified solubilized Ca2+, Mg(2+)-ATPase from myometrium cell plasma membranes and Ca(2+)-transporting activity of this enzyme reconstituted into azolectin liposomes: 10 mM NaF plus 10 microM AlCl3 inhibited the primary activity by 95% and--by 81%. Inhibition of purified both solubilized and reconstituted Ca2+, Mg(2+)-ATPases by fluoroaluminate evidences for the possibility of direct interaction AlF4- with this enzyme without involvement of G-protein. The sensitivity to fluoroaluminate of sarcolemmal Ca2+, Mg(2+)-ATPase from myometrium is similar to that of Ca2+, Mg(2+)-ATPase from stomach smooth muscle.