Mutual recognition between polymerized liposomes: enzyme and enzyme inhibitor system.

In order to examine the usefulness of polymerized liposomes as a model for cell membranes, a mutual recognition phenomenon between different liposomes on which complementary ligands were attached was examined. We used trypsin- and soybean trypsin inhibitor (STI)-carrying polymerized liposomes to attain high sensitivities. The STI which was immobilized on the polymerized mono-dienoylphosphatidylcholine liposome showed a definite inhibitory effect on the catalytic activity of the trypsin which was immobilized on another polymerized liposome, whereas the inhibitory effect of the STI which was immobilized on the di-dienoylphosphatidylcholine liposome was much smaller than that of the mono-dienoylphosphatidylcholine system because of the larger rigity of the di-dienoylphosphatidylcholine liposome. These results suggest that the mutual recognition between complementary ligands can be realized by using polymerized liposomes with a physical stability and moderate deformability as their carriers.