Abstract
Mouse liver microsomes treated with octylthioglucoside were examined for iron-stimulated ATPase activity. The activity was about 6 μmol Pi/mg protein/hr under optimal conditions [300mM KCI, 3 mM MgSO4, 10 mM glutathione (GSH), 100μM FeCl3, 3 mM ATP and 50 mM acetate buffer at pH 5.0]. The Km for iron was 20 μM. A reducing agent, such as GSH or dithiothreitol, was required for the activity, and removal of Fe2+ from the reaction mixture by bathophenan-throlinedisulfonate resulted in a complete loss of the iron-stimulated ATPase activity. Vanadate inhibited the iron-stimulated ATPase activity. These results suggest that microsomes from mouse liver contain the Fe2+ -stimulated P-type ATPase.
