Scanning electrochemical microscopy of menadione-glutathione conjugate export from yeast cells
AUTOR(ES)
Mauzeroll, Janine
FONTE
National Academy of Sciences
RESUMO
The uptake of menadione (2-methyl-1,4-naphthoquinone), which is toxic to yeast cells, and its expulsion as a glutathione complex were studied by scanning electrochemical microscopy. The progression of the in vitro reaction between menadione and glutathione was monitored electrochemically by cyclic voltammetry and correlated with the spectroscopic (UV–visible) behavior. By observing the scanning electrochemical microscope tip current of yeast cells suspended in a menadione-containing solution, the export of the conjugate from the cells with time could be measured. Similar experiments were performed on immobilized yeast cell aggregates stressed by a menadione solution. From the export of the menadione-glutathione conjugate detected at a 1-μm-diameter electrode situated 10 μm from the cells, a flux of about 30,000 thiodione molecules per second per cell was extracted. Numerical simulations based on an explicit finite difference method further revealed that the observation of a constant efflux of thiodione from the cells suggested the rate was limited by the uptake of menadione and that the efflux through the glutathione-conjugate pump was at least an order of magnitude faster.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=419522Documentos Relacionados
- Menadione metabolism to thiodione in hepatoblastoma by scanning electrochemical microscopy
- Application of scanning electrochemical microscopy to biological samples.
- Scanning electrochemical microscopy of living cells: Different redox activities of nonmetastatic and metastatic human breast cells
- Photosynthetic Electron Transport in Single Guard Cells as Measured by Scanning Electrochemical Microscopy.
- Scanning electron microscopy of lymphoid cells from leukemia virus-infected mice.