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Thomas Lötzbeyer
Technische Universität München
Electron transferInorganic chemistryChemistryHorseradish peroxidaseEnzyme electrode
6Publications
6H-index
453Citations
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Publications 6
Newest
#1Thomas Lötzbeyer (TUM: Technische Universität München)H-Index: 6
#2Wolfgang Schuhmann (RUB: Ruhr University Bochum)H-Index: 68
Last. Hanns-Ludwig Schmidt (TUM: Technische Universität München)H-Index: 36
view all 3 authors...
Abstract Direct electron transfer between an immobilized biological compound and an electrode is one of the most interesting transduction processes for the development of fast responding amperometric biosensors. Different biocatalysts like horseradish peroxidase, cytochrome c, myoglobin, microperoxidase MP-11 and haemin, all of them catalyzing the reduction of H2O2, have been investigated aiming on their ability for direct electron-transfer reactions when covalently tethered to self-assembled mo...
72 CitationsSource
#1Christine Kranz (TUM: Technische Universität München)H-Index: 32
#2Thomas Lötzbeyer (TUM: Technische Universität München)H-Index: 6
Last. Wolfgang Schuhmann (TUM: Technische Universität München)H-Index: 68
view all 4 authors...
Abstract Lateral-resolved visualization of direct electron transfer between cystamine-monolayer modified planar gold electrodes with covalently bound microperoxidase MP-11 is possible using the feedback mode of scanning electrochemical microscopy (SECM). At a potential of the modified gold electrode of −500 mV versus Ag/AgCl the heme center of microperoxidase can be reduced by means of direct electrochemical communication, and a suitable redox mediator, which is oxidized at the microtip electrod...
11 CitationsSource
#1Thomas Lötzbeyer (TUM: Technische Universität München)H-Index: 6
#2Wolfgang Schuhmann (TUM: Technische Universität München)H-Index: 68
Last. Hanns-Ludwig Schmidt (TUM: Technische Universität München)H-Index: 36
view all 3 authors...
Abstract The most promising approach for the development of reagentless enzyme electrodes is to establish a direct electrical communication between the enzyme and the electrode surface. We could demonstrate for monolayer-immobilized enzymes catalyzing the reduction of H 2 O 2 (e.g. cytochrome c , microperoxidase MP-11 and horseradish peroxidase) that their catalytic activity in solution is not correlated with their abilities for direct electrochemical communication with the electrode when immobi...
76 CitationsSource
#1Thomas Lötzbeyer (TUM: Technische Universität München)H-Index: 6
#2Wolfgang Schuhmann (TUM: Technische Universität München)H-Index: 68
Last. Hanns-Ludwig Schmidt (TUM: Technische Universität München)H-Index: 36
view all 3 authors...
43 CitationsSource
#1Thomas LötzbeyerH-Index: 6
#2Wolfgang Schuhmann (TUM: Technische Universität München)H-Index: 68
Last. Hanns-Ludwig Schmidt (TUM: Technische Universität München)H-Index: 36
view all 5 authors...
A fundamental prerequisite for the development of reagentless amperometric biosensors is the control over electron-transfer processes between immobilized biocatalytical recognition systems, e.g. enzymes, and the surface of a suitable electrode. According to Marcus’ theory [l], the electron-transfer rate is governed by the potential difference, the reorganisation energy and, most significantly for the development of enzyme electrodes, the distance between the involved redox centers. Thus, alterna...
97 CitationsSource
#1Eugenii Katz (TUM: Technische Universität München)H-Index: 69
#2Thomas Lötzbeyer (TUM: Technische Universität München)H-Index: 6
Last. Hanns-Ludwig Schmidt (TUM: Technische Universität München)H-Index: 36
view all 5 authors...
Chemisorption of cystamine and cysteamine was used for functionalization of Au and Pt electrodes, respectively with amino groups. The functionalized electrodes were used for covalent immobilization of pyrroloquinoline quinone (PQQ) as a monolayer by carbodiimide coupling of the PQQ carboxylic groups with the surface amino groups. The electrochemical properties of the PQQ-modified electrodes (formal potential E°, peak currents Ip and peak-to-peak separation ΔE) were changed after addition of Ca2+...
157 CitationsSource
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