Direct Electron Transfer of Enzymes Facilitated by Cytochromes. Issue 4 (13th December 2018)

• Record Type: Journal Article
• Authors: Ma, Su; Ludwig, Roland
• Is Part Of: ChemElectroChem. Volume 6:Issue 4(2019)
• Page Start: 958
• Page End: 975
• Publication Date: 2018-12-13
• Subjects: cytochrome -- direct electron transfer -- direct electrochemistry -- flavin -- flavocytochrome -- haem -- molybdenum -- multi-cofactor enzyme -- pyrrolinoquinoline quinone -- iron-sulfur cluster; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201801256
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: The direct electron transfer (DET) of enzymes has been utilized to develop biosensors and enzymatic biofuel cells on micro‐ and nanostructured electrodes. Whereas some enzymes exhibit direct electron transfer between their active‐site cofactor and an electrode, other oxidoreductases depend on acquired cytochrome domains or cytochrome subunits as built‐in redox mediators. The physiological function of these cytochromes is to transfer electrons between the active‐site cofactor and a redox partner protein. The exchange of the natural electron acceptor/donor by an electrode has been demonstrated for several cytochrome carrying oxidoreductases. These multi‐cofactor enzymes have been applied in third generation biosensors to detect glucose, lactate, and other analytes. This review investigates and classifies oxidoreductases with a cytochrome domain, enzyme complexes with a cytochrome subunit, and covers designed cytochrome fusion enzymes. The structurally and electrochemically best characterized proponents from each enzyme class carrying a cytochrome, that is, flavoenzymes, quinoenzymes, molybdenum‐cofactor enzymes, iron‐sulfur cluster enzymes, and multi‐haem enzymes, are featured, and their biochemical, kinetic, and electrochemical properties are compared. The cytochromes molecular and functional properties as well as their contribution to the interdomain electron transfer (IET, between active‐site and cytochrome) and DET (between cytochrome and electrode) with regard to the achieved current density is discussed. Protein design strategies for cytochrome‐fused enzymes are reviewed and the limiting factors as well as strategies to overcome them are outlined. Abstract : It′s classified : Multi‐cofactor enzymes with a cytochrome domain use it to transfer electrons to physiological redox partner proteins, but the cytochrome can also establish direct electron transfer (DET) to electrodes. The enzymes are classified, compared, and analyzed in terms of their redox and DET properties to obtain guidelines for selecting and designing suitable enzymes for third‐generation biosensors.