Electron transfer between redox enzymes and electrodes through the artificial redox proteins and its application for biosensors

Three kinds of artificial redox proteins have been designed and prepared in order to discuss their applicability for the facile electron transferring interfaces between redox enzymes and electrode materials. First, ferrocene derivative-modified bovine serum albumin was prepared and was adsorbed together with fructose dehydrogenase on the conductive SnO₂ electrode to fabricate an enzyme sensor for fructose. Second, avidins, which were chemically modified with anthraquinonyl group or pyrroloquinoline quinone (PQQ), were prepared. They were assembled onto biotin-modified gold electrode surfaces and their redox properties at the surface-bound state were electrochemically studied. Third, the genetically engineered streptavidin into which a redox-active non-nature amino acid, anthraquinonylalanine was incorporated at a specific site was synthesized and characterized as an artificial redox protein.