IMMOBILIZATION OF ACETYLCHOLINESTERASE ON SOLID-SURFACES - CHEMISTRY AND ACTIVITY STUDIES

A method for covalent attachment of the enzyme acetylcholinesterase (E.C. 3.1.1.7, Electric Eel) on two different solid surfaces (glass and platinum) is described. The chemistry includes covalent bond formation between a hydroxyl group on the surface, a thiol-terminal silane, a heterobifunctional crosslinker, and the enzyme. The activity of the immobilized enzyme has been determined spectrophotometrically using two different substrates, acetylcholine and butyrylthiocholine. It is determined that after immobilization, acetylcholinesterase retains at least 50% of its activity on glass and 15% of its activity on platinum surfaces when assayed using butyrylthiocholine as a substrate. The general procedure described here for the immobilization of enzymes should find broad use in the fabrication of enzyme electrodes and in biosensor technology.