TY  - JOUR
A1  - Neumann, Bettina
A1  - Kielb, Patrycja
A1  - Rustam, Lina
A1  - Fischer, Anna
A1  - Weidinger, Inez M.
A1  - Wollenberger, Ulla
T1  - Bioelectrocatalytic Reduction of Hydrogen Peroxide by Microperoxidase-11 Immobilized on Mesoporous Antimony-Doped Tin Oxide
JF  - ChemElectrChem
N2  - The heme-undecapeptide microperoxidase-11 (MP-11) was immobilized on mesoporous antimony-doped tin oxide (ATO) thin-film electrodes modified with the positively charged binding promotor polydiallyldimethylammonium chloride. Surface concentrations of MP-11 of 1.5 nmol cm(-2) were sufficiently high to enable spectroelectrochemical analyses. UV/Vis spectroscopy and resonance Raman spectroscopy revealed that immobilized MP-11 adopts a six-coordinated low-spin conformation, as in solution in the presence of a polycation. Cathodic reduction of hydrogen peroxide at potentials close to +500mV versus Ag/AgCl indicates that the reaction proceeds via a Compound I-type like intermediate, analogous to natural peroxidases, and confirms mesoporous ATO as a suitable host material for adsorbing the heme-peptide in its native state. A hydrogen peroxide sensor is proposed by using the bioelectrocatalytic properties of the MP-11-modified ATO.
KW  - electrochemistry
KW  - enzyme catalysis
KW  - mesoporous materials
KW  - microperoxidase
KW  - spectroelectrochemistry
Y1  - 2017
U6  - https://doi.org/10.1002/celc.201600776
SN  - 2196-0216
VL  - 4
IS  - 4
SP  - 913
EP  - 919
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Kielb, Patrycja
A1  - Sezer, Murat
A1  - Katz, Sagie
A1  - Lopez, Francesca
A1  - Schulz, Christopher
A1  - Gorton, Lo
A1  - Ludwig, Roland
A1  - Wollenberger, Ursula
A1  - Zebger, Ingo
A1  - Weidinger, Inez M.
T1  - Spectroscopic Observation of Calcium-Induced Reorientation of Cellobiose Dehydrogenase Immobilized on Electrodes and its Effect on Electrocatalytic Activity
JF  - ChemPhysChem : a European journal of chemical physics and physical chemistry
N2  - 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.
KW  - cellobiose dehydrogenase
KW  - electron transfer
KW  - enzyme catalysis
KW  - spectroelectrochemistry
KW  - surface-enhanced vibrational spectroscopy
Y1  - 2015
U6  - https://doi.org/10.1002/cphc.201500112
SN  - 1439-4235
SN  - 1439-7641
VL  - 16
IS  - 9
SP  - 1960
EP  - 1968
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Albrecht, Steve
A1  - Vandewal, Koen
A1  - Tumbleston, John R.
A1  - Fischer, Florian S. U.
A1  - Douglas, Jessica D.
A1  - Frechet, Jean M. J.
A1  - Ludwigs, Sabine
A1  - Ade, Harald W.
A1  - Salleo, Alberto
A1  - Neher, Dieter
T1  - On the efficiency of charge transfer state splitting in polymer: Fullerene solar cells
JF  - Advanced materials
KW  - organic solar cells
KW  - charge generation
KW  - geminate recombination
KW  - charge transfer states
KW  - driving force
KW  - excess energy
KW  - morphology
KW  - spectroelectrochemistry
Y1  - 2014
U6  - https://doi.org/10.1002/adma.201305283
SN  - 0935-9648
SN  - 1521-4095
VL  - 26
IS  - 16
SP  - 2533
EP  - 2539
PB  - Wiley-VCH
CY  - Weinheim
ER  -