@article{KielbSezerKatzetal.2015,
  author    = {Kielb, Patrycja and Sezer, Murat and Katz, Sagie and Lopez, Francesca and Schulz, Christopher and Gorton, Lo and Ludwig, Roland and Wollenberger, Ursula and Zebger, Ingo and Weidinger, Inez M.},
  title     = {Spectroscopic Observation of Calcium-Induced Reorientation of Cellobiose Dehydrogenase Immobilized on Electrodes and its Effect on Electrocatalytic Activity},
  series = {ChemPhysChem : a European journal of chemical physics and physical chemistry},
  volume    = {16},
  journal   = {ChemPhysChem : a European journal of chemical physics and physical chemistry},
  number    = {9},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1439-4235},
  doi       = {10.1002/cphc.201500112},
  pages     = {1960 -- 1968},
  year      = {2015},
  abstract  = {Cellobiose dehydrogenase catalyzes the oxidation of various carbohydrates and is considered as a possible anode catalyst in biofuel cells. It has been shown that the catalytic performance of this enzyme immobilized on electrodes can be increased by presence of calcium ions. To get insight into the Ca2+-induced changes in the immobilized enzyme we employ surface-enhanced vibrational (SERR and SEIRA) spectroscopy together with electrochemistry. Upon addition of Ca2+ ions electrochemical measurements show a shift of the catalytic turnover signal to more negative potentials while SERR measurements reveal an offset between the potential of heme reduction and catalytic current. Comparing SERR and SEIRA data we propose that binding of Ca2+ to the heme induces protein reorientation in a way that the electron transfer pathway of the catalytic FAD center to the electrode can bypass the heme cofactor, resulting in catalytic activity at more negative potentials.},
  language  = {en}
}
@article{SpricigoLeimkuehlerGortonetal.2015,
  author    = {Spricigo, Roberto and Leimk{\"u}hler, Silke and Gorton, Lo and Scheller, Frieder W. and Wollenberger, Ursula},
  title     = {The Electrically Wired Molybdenum Domain of Human Sulfite Oxidase is Bioelectrocatalytically Active},
  series = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe},
  journal   = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe},
  number    = {21},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1434-1948},
  doi       = {10.1002/ejic.201500034},
  pages     = {3526 -- 3531},
  year      = {2015},
  abstract  = {We report electron transfer between the catalytic molybdenum cofactor (Moco) domain of human sulfite oxidase (hSO) and electrodes through a poly(vinylpyridine)-bound [osmium(N,N'-methyl-2,2'-biimidazole)(3)](2+/3+) complex as the electron-transfer mediator. The biocatalyst was immobilized in this low-potential redox polymer on a carbon electrode. Upon the addition of sulfite to the immobilized separate Moco domain, the generation of a significant catalytic current demonstrated that the catalytic center is effectively wired and active. The bioelectrocatalytic current of the wired separate catalytic domain reached 25\% of the signal of the wired full molybdoheme enzyme hSO, in which the heme b(5) is involved in the electron-transfer pathway. This is the first report on a catalytically active wired molybdenum cofactor domain. The formal potential of this electrochemical mediator is between the potentials of the two cofactors of hSO, and as hSO can occupy several conformations in the polymer matrix, it is imaginable that electron transfer from the catalytic site to the electrode through the osmium center occurs for the hSO molecules in which the Moco domain is sufficiently accessible. The observation of catalytic oxidation currents at low potentials is favorable for applications in bioelectronic devices.},
  language  = {en}
}