ABSTRACT
Many enzymes function in nature while bound to membranes [4]. Biological membranes are about half protein and half phospholipid. Proteins are bound on the outer surfaces of the membrane, partly inserted into the bilayer, or extended across the biomembranes (Figure 1). Yokota and coworkers reported direct, reversible voltammetry for cytochrome c (cyt c) on a phosphatidylcholine LangmuirBlodgett membrane transferred to an ITO electrode in 1987 [5]. Tien and Salamon [6] developed a simple method for adsorbing a lipid bilayer onto a metal electrode. An insulated metal wire is cleaved in a droplet of lipid in organic solvent. Lipid molecules adsorb onto the freshly cleaved surface. The adsorbed film thins to a lipid bilayer in water and is stable for 36 hr. Salamon and Tollin employed this method with mixed phosphatidylcholines films to reduce cyt c [7, 8].
