both the divalent cation ionophore , a23187 , and the monovalent cation ionophore , valinomycin , significantly enhance phosphatidylinositol transfer in the standard reaction mixture at concentrations 1 to 2 orders of magnitude greater than those sufficient for the ionophores to facilitate cation transport across membranes .
C0007448
divalent cation
C0007447
cation