TY - JOUR A1 - Lettau, Kristian A1 - Warsinke, Axel A1 - Katterle, Martin A1 - Danielsson, Bengt A1 - Scheller, Frieder W. T1 - A bifunctional molecularly imprinted polymer (MIP): analysis of binding and catalysis by a thermistor N2 - Binding or catalysis? Both can be distinguished with a molecularly imprinted polymer (MIP) by the different patterns of heat generation. The catalytically active sites, like in the corresponding enzyme, generate a steady-state temperature increase. Thus, enzyme-like catalysis and antibody-analogue binding are analyzed simultaneously in a bifunctional MIP for the first time (see scheme). Y1 - 2006 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/26737/ U6 - https://doi.org/10.1002/anie.200601796 ER - TY - JOUR A1 - Katterle, Martin A1 - Holzwarth, Alfred R. A1 - Jesorka, Aldo T1 - A Heck-type coupling for the synthesis of novel bridged metallochlorin-fullerene C-60 dyads N2 - A short and convenient synthesis of metallochlorin-C-60 dyads based on a Heck-type hetero coupling at the 3(2) position of a chlorin is described. p-Bromobenzaldehyde was treated with Zn-metalated 13(2)- demethoxycarbonylmethylpheophorbide a, using a palladium acetate/LiCl catalyst mixture under phase-transfer conditions in DMF at 70 degrees C. The resulting asymmetric olefin was obtained in a high trans/cis ratio. The desired trans isomer was separated and subsequently transformed into a donor-acceptor dyad by a 1,3-dipolar cycloaddition to C-60 in the presence of sarcosine in refluxing toluene. The resulting dyads are expected to undergo efficient photoinduced electron transfer and can potentially be utilized in solar energy conversion devices. Y1 - 2006 UR - http://www3.interscience.wiley.com/cgi-bin/jhome/27380/ U6 - https://doi.org/10.1002/ejoc.200500494 SN - 1434-193X ER - TY - JOUR A1 - Loew, Noya A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. A1 - Katterle, Martin T1 - Direct electrochemistry and spectroelectrochemistry of osmium substituted horseradish peroxidase N2 - In this contribution the substitution of the central protoporphyrin IX iron complex of horseradish peroxidase by the respective osmium porphyrin complex is described. The direct electrochemical reduction of the Os containing horseradish peroxidase (OsHRP) was achieved at ITO and modified glassy carbon electrodes and in combination with spectroscopy revealed the three redox couples (OsHRP)-H-III/(OsHRP)-H-IV, (OsHRP)-H-IV/(OsHRP)-H-V and (OsHRP)-H-V/ (OsHRP)-H-VI. The midpoint potentials differ dependent on the electrode material used with E-1/2 (Os-III/IV) of -0.4 V (ITO) and -0.25 V (GC), E-1/2 (Os-IV/V) of -0.16 V (ITO) and +0.10 V (GC), and E-1/2 (Os-V/VI)of +018 V (ITO), respectively Moreover, with immobilised OsHRP the direct electrocatalytic reduction of hydrogen peroxide and tert-butyl hydroperoxide was observed. In comparison to electrodes modified with native HRP the sensitivity of the OsHRP-electrode for tert-butyl hydroperoxide is higher. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/15675394 U6 - https://doi.org/10.1016/j.bioelechem.2009.03.015 SN - 1567-5394 ER - TY - JOUR A1 - Katterle, Martin A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. T1 - Electrochemistry of hemoglobin at modified silver electrodes is not a redox-process of iron protoporhyrin IX Y1 - 1997 ER - TY - JOUR A1 - Liu, Songqin A1 - Wollenberger, Ursula A1 - Katterle, Martin A1 - Scheller, Frieder W. T1 - Ferroceneboronic acid-based amperometric biosensor for glycated hemoglobin N2 - An amperometric biosensor for the determination of glycated hemoglobin in human whole blood is proposed. The principle is based on the electrochemical measurement of ferroceneboronic acid (FcBA) that has been specifically bound to the glycated N-terminus. Hemoglobin is immobilized on a zirconium dioxide nanoparticle modified pyrolytic graphite electrode (PGE) in the presence of didodecyldimethylammonium bromide (DDAB). The incubation of this sensor in FcBA solution leads to the formation of an FcBA-modified surface due to the affinity interaction between boronate and the glycated sites of the hemoglobin. The binding of FcBA results in well-defined redox peaks with an E-0' of 0.299 V versus Ag/AgCl (1 M KCl). The square wave voltammetric response of the bound FcBA reflects the amount of glycated hemoglobin at the surface. This signal increases linearily with the degree of glycated hemoglobin from 6.8 to 14.0% of total immobilized hemoglobin. The scheme was applied to the determination of the fraction of glycated hemoglobin in whole blood samples. Y1 - 2006 UR - http://www.sciencedirect.com/science/journal/09254005 U6 - https://doi.org/10.1016/j.snb.2005.07.011 SN - 0925-4005 ER - TY - JOUR A1 - Loew, Noya A1 - Bogdanoff, Peter A1 - Herrmann, Iris A1 - Wollenberger, Ursula A1 - Scheller, Frieder W. A1 - Katterle, Martin T1 - Influence of modifications on the efficiency of pyrolysed CoTMPP as electrode material for horseradish peroxidase and the reduction of hydrogen peroxide JF - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis N2 - 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. KW - cobalt porphyrin KW - electron transfer KW - horseradish peroxidase KW - hydrogen peroxide KW - immobilization Y1 - 2006 U6 - https://doi.org/10.1002/elan.200603664 SN - 1040-0397 VL - 18 IS - 23 SP - 2324 EP - 2330 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Litwinski, Christian A1 - Tannert, Sebastian A1 - Jesorka, Aldo A1 - Katterle, Martin A1 - Roder, Beate T1 - Photophysical properties of gallium hydroxyl tetratolylporphyrin and 13(2)-demethoxycarbonyl-(gallium hydroxyl)- methyl-pheophorbide alpha N2 - Two metal tetrapyrroles containing gallium, gallium hydroxyl tetratolylporphyrin and 13(2)-demethoxycarbonyl- (gallium hydroxyl)methyl pheophorbide a (Ga-(OH)-chlorin), were synthesized from their respective free bases using Ga(III)-acetylacetonate in a phenol melt. Their photophysical properties were investigated and the quantum yields of different monomolecular deactivation processes were determined. For Ga-(OH)-porphyrin S-2-fluorescence was observed and quantified. In contrast. for Ga-(OH)-chlorin no S-2-fluorescence was observed. Both compounds should be useful as efficient photosensitizers in photodynamic therapy. Y1 - 2006 UR - http://www.sciencedirect.com/science/journal/00092614 U6 - https://doi.org/10.1016/j.cplett.2005.10.131 SN - 0009-2614 ER - TY - JOUR A1 - Scheller, Frieder W. A1 - Bistolas, Nikitas A1 - Liu, Songqin A1 - Jänchen, Michael A1 - Katterle, Martin A1 - Wollenberger, Ursula T1 - Thirty years of haemoglobin electrochemistry N2 - Electrochemical investigations of the blood oxygen carrier protein include both mediated and direct electron transfer. The reaction of haemoglobin (Hb) with typical mediators, e.g., ferricyanide, can be quantified by measuring the produced ferrocyanide which is equivalent to the Hb concentration. Immobilization of the mediator within the electrode body allows reagentless electrochemical measuring of Hb. On the other hand, entrapment of the protein within layers of polyclectrolytes, lipids, nanoparticles of clay or gold leads to a fast heterogeneous electron exchange of the partially denatured Hb. (c) 2005 Elsevier B.V. All rights reserved Y1 - 2005 ER -