Interaction of basic compounds with coated vesicles.

The effect of poly- and dibasic amines, including chloroquine and quinacrine, on the dissociation of coated vesicles at pH 7.4 in 0.01 M 2-(N-morpholino)ethanesulfonic acid has been evaluated by light scattering and sucrose gradient centrifugation. The degree of inhibition of dissociation by the polybases is proportional to the number of amine groups in each compound. However, very little difference in effectiveness was found in a series of dibasic compounds, NH2(CH2)2-5NH2. Chloroquine and quinacrine contain dibasic aliphatic chains as well as aromatic ring systems. These two antimalarials are more effective in inhibiting dissociation of coated vesicles than the dibasic aliphatic amines. The ring systems therefore appear to be contributing, independently, to the free energy of stabilization of the coat structure of coated vesicles. It is suggested that the interaction of poly- or dibasic compounds with clathrin or coated vesicles could influence the turnover of ligands in receptor-mediated endocytosis.