@article{WegerichTuranoAllegrozzietal.2009,
  author    = {Wegerich, Franziska and Turano, Paola and Allegrozzi, Marco and Moehwald, Helmuth and Lisdat, Fred},
  title     = {Cytochrome c mutants for superoxide biosensors},
  issn      = {0003-2700},
  doi       = {10.1021/Ac802571h},
  year      = {2009},
  abstract  = {The effect of introducing positive charges (lysines) in human cytochrome c (cyt c) on the redox properties and reaction rates of cyt c with superoxide radicals was studied. The mutated forms of this electron-transfer protein are used as sensorial recognition elements for the amperometric detection of the reactive oxygen radical. The proteins were prepared by site-directed mutagenesis focusing on amino acids near the heme edge. The 11 mutants of human cyt c expressed in the course of this research have been characterized by UV-vis spectroscopy, circular dichroism, and NMR spectroscopy to verify overall structure integrity as well as axial coordination of the heme iron. The mutants are investigated voltammetrically using promoter-modified gold electrodes with respect to redox activity and formal redox potential. The rate constants for the reaction with superoxide have been determined spectrophotometrically. Four mutants show a higher reaction rate with the radical as compared to the wild type. These mutants are used for the construction of superoxide sensors based on thiol-modified gold electrodes and covalently fixed proteins. We found that the E66K mutant-based electrode has a clearly higher sensitivity in comparison with the wild-type-based sensor while retaining the high selectivity and showing a good storage stability.},
  language  = {en}
}