Composite films of lecithin and heme proteins with electrochemical and electrocatalytic activities

Functional composite films made from lecithin micelles and the two heme proteins of met-myoglobin (Mb) and met-hemoglobin (Hb) are reported in this paper. Proteins in functional composite films have much higher rates of electron transfer than proteins in solutions on carbon paste (CP) electrodes. Cyclic voltammograms (CVs) all give a pair of well-defined and quasi-reversible peaks, corresponding to the heme FeIII/FeII redox couple of proteins. Differential pulse voltammograms (DPVs) also show the same formal potential (E0′) values of proteins under identical conditions. Electronic and vibrational spectra indicate that proteins in these films are not denatured, but their conformational differences from native states may exist. The E0′ value for Mb in the lecithin film is found to be pH dependent. The Mb lecithin film can catalytically reduce O2 and H2O2, and its analytical application to H2O2 determination is established.

Graphical abstractComposite films of Hb and Mb in lecithin micelles display direct electron transfer with E0′ values of −0.374 and −0.338 V−0.338 V, respectively, in pH 7.0 phosphate buffers.Figure optionsDownload full-size imageDownload as PowerPoint slide