COUPLING OF PROTON TRANSLOCATION THROUGH ATPASE INCORPORATED INTO SUPPORTED LIPID BILAYERS TO AN ELECTROCHEMICAL PROCESS

H+-ATPase is incorporated into solid-supported lipid bilayers separate d from the gold support by a peptide spacer. The translocation of prot ons across the lipid film to the inner side is coupled to the discharg e of protons at the gold surface. The overall process is investigated by square wave voltammetry (SWV) and double potential-pulse chronoampe rometry (CA). As a result, the formation of a proton gradient is monit ored by SWV whereas currents measured by CA monitor the stationary sta te when the enzyme activity is directly coupled to the charge transfer at the electrode. These currents markedly depend on the number of ATP ases present in the bilayer. (C) 1997 Elsevier Science S.A.