Control of enzymic activity by artificial cell-surface receptors

A novel type of artificial cell-surface receptor capable of affecting enzymic activity was designed by employing steroidal moiety. Bile acid derivatives having an amino group, effectively recognized both the aromatic aldehydes and copper(II) ions in bilayer membrane formed with a synthetic peptide lipid. On the other hand, pig heart l-lactate dehydrogenase (LDH) was bound to the bilayer membrane surface mainly through electrostatic interactions, and the LDH activity was specifically inhibited by copper(II) ions. On these grounds, we constituted artificial signaling systems in combinations, with a steroidal receptor, a bilayer-forming synthetic lipid, and LDH. The present supramolecular vesicles acted as nano-reactors in which the artificial receptor was able to switch on the enzymic activity via accompanying double signal recognition and phase reorganization.