title: Electrochemical detection of intracellular and cell membrane redox systems in Saccharomyces cerevisiae.
abstract: Redox mediators can interact with eukaryote cells at a number of different cell locations. While cell membrane redox centres are easily accessible, the redox centres of catabolism are situated within the cytoplasm and mitochondria and can be difficult to access. We have systematically investigated the interaction of thirteen commonly used lipophilic and hydrophilic mediators with the yeast Saccharomyces cerevisiae. A double mediator system is used in which ferricyanide is the final electron acceptor (the reporter mediator). After incubation of cells with mediators, steady state voltammetry of the ferri/ferrocyanide redox couple allows quantitation of the amount of mediator reduced by the cells. The plateau current at 425 mV vs Ag/AgCl gives the analytical signal. The results show that five of the mediators interact with at least three different trans Plasma Membrane Electron Transport systems (tPMETs), and that four mediators cross the plasma membrane to interact with cytoplasmic and mitochondrial redox molecules. Four of the mediators inhibit electron transfer from S. cerevisiae. Catabolic inhibitors were used to locate the cellular source of electrons for three of the mediators.
authors.affiliation: 1] Laboratory of Biophysics and Surfaces Analysis, School of Pharmacy, University of Nottingham, University Park, Nottingham B15 2TT UK [2] Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Frankie J
authors.initials: FJ
authors.lastname: Rawson
authors.affiliation: 1] Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch, New Zealand [2] MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Alison J
authors.initials: AJ
authors.lastname: Downard
authors.affiliation: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Keith H
authors.initials: KH
authors.lastname: Baronian
mesh_terms: D002462:Cell Membrane / Q000378:metabolism* / Q000502:physiology*; D003593:Cytoplasm / Q000378:metabolism / Q000502:physiology; D004579:Electron Transport / Q000502:physiology*; D005292:Ferricyanides / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism / Q000502:physiology; D010084:Oxidation-Reduction; D012441:Saccharomyces cerevisiae / Q000378:metabolism* / Q000502:physiology*
chemical_list: D005292:Ferricyanides; C007931:hexacyanoferrate III