Glucocorticoid receptor stabilization: relative effects of molybdate ion on inactivation by alkaline phosphatase and phospholipase A2.

Glucocorticoid receptors in cytosol preparations from rat liver or mouse L cells are inactivated by phospholipase A2 or calf intestine alkaline phosphatase. Molybdate ion, an inhibitor of a variety of phosphatase enzymes, does not prevent inactivation of glucocorticoid binding capacity by alkaline phosphatase but it blocks inactivation by phospholipase A2. In neither case is the enzyme itself inhibited, and the effect of molybdate on phospholipase-mediated inactivation appears to reflect the ability of molybdate to prevent receptor inactivation by the detergent action of lysophosphatides.