CMP-dependent phosphatidylinositol:myo-inositol exchange activity in isolated nerve-endings

Greatly enhanced manganese-dependent phosphatidylinositol:myo-inositol exchange activity was observed when isolated, intact nerve-endings were incubated with the nucleotide, CMP, suggesting that the enzyme, CDP-diglyceride:inositol phosphatidyl transferase, catalyzes this exchange. CMP, at 10 microM, produced as much myo-[2-3H] inositol incorporation into phosphatidylinositol as did 1 mM. This CMP-stimulated exchange activity may reside on the plasma membrane.