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 - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/31773 UR - http://www.sciencedirect.com/science/journal/15675394 SN - 1567-5394 ER -