@article{LoewBogdanoffHerrmannetal.2006,
  author    = {Loew, Noya and Bogdanoff, Peter and Herrmann, Iris and Wollenberger, Ursula and Scheller, Frieder W. and Katterle, Martin},
  title     = {Influence of modifications on the efficiency of pyrolysed CoTMPP as electrode material for horseradish peroxidase and the reduction of hydrogen peroxide},
  series = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
  volume    = {18},
  journal   = {Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis},
  number    = {23},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1040-0397},
  doi       = {10.1002/elan.200603664},
  pages     = {2324 -- 2330},
  year      = {2006},
  abstract  = {A tailor-made horseradish peroxidase (HRP) bulk composite electrode was developed on the basis of pyrolyzed cobalt tetramethoxyphenylporphyrin (CoTMPP) by modifying pore size and surface area of the porous carbon material through varying amounts of iron oxalate and sulfur prior to pyrolyzation. The materials were used to immobilize horseradish peroxidase (HRP). These electrodes were characterized in terms of their efficiency to reduce hydrogen peroxide. The heterogeneous electron transfer rate constants of different materials were determined with the rotating disk electrode method and a k(S) (401 +/- 61 s(-1)) exceeding previously reported values for native HRP was found.},
  language  = {en}
}
@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{PengUteschYarmanetal.2015,
  author    = {Peng, Lei and Utesch, Tillmann and Yarman, Aysu and Jeoung, Jae-Hun and Steinborn, Silke and Dobbek, Holger and Mroginski, Maria Andrea and Tanne, Johannes and Wollenberger, Ursula and Scheller, Frieder W.},
  title     = {Surface-Tuned Electron Transfer and Electrocatalysis of Hexameric Tyrosine-Coordinated Heme Protein},
  series = {Chemistry - a European journal},
  volume    = {21},
  journal   = {Chemistry - a European journal},
  number    = {20},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.201405932},
  pages     = {7596 -- 7602},
  year      = {2015},
  abstract  = {Molecular modeling, electrochemical methods, and quartz crystal microbalance were used to characterize immobilized hexameric tyrosine-coordinated heme protein (HTHP) on bare carbon or on gold electrodes modified with positively and negatively charged self-assembled monolayers (SAMs), respectively. HTHP binds to the positively charged surface but no direct electron transfer (DET) is found due to the long distance of the active sites from the electrode surfaces. At carboxyl-terminated surfaces, the neutrally charged bottom of HTHP can bind to the SAM. For this "disc" orientation all six hemes are close to the electrode and their direct electron transfer should be efficient. HTHP on all negatively charged SAMs showed a quasi-reversible redox behavior with rate constant k(s) values between 0.93 and 2.86 s(-1) and apparent formal potentials E-app(0)' between -131.1 and -249.1 mV. On the MUA/MU-modified electrode, the maximum surface concentration corresponds to a complete monolayer of the hexameric HTHP in the disc orientation. HTHP electrostatically immobilized on negatively charged SAMs shows electrocatalysis of peroxide reduction and enzymatic oxidation of NADH.},
  language  = {en}
}