@misc{PengWollenbergerKinneetal., author = {Peng, Lei and Wollenberger, Ulla and Kinne, Matthias and Hofrichter, Martin and Ullrich, Ren{\´e} and Scheibner, Katrin and Fischer, Anna and Scheller, Frieder W.}, title = {Peroxygenase based sensor for aromatic compounds}, series = {Biosensors and Bioelectronics}, volume = {26}, journal = {Biosensors and Bioelectronics}, number = {4}, issn = {1873-4235}, doi = {10.1016/j.bios.2010.07.075}, url = {http://nbn-resolving.de/http://www.sciencedirect.com/science/article/pii/S0956566310004501}, pages = {1432 -- 1436}, abstract = {We report on the redox behaviour of the peroxygenase from Agrocybe aegerita (AaeAPO) which has been electrostatically immobilized in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode. AaeAPO contains a covalently bound heme-thiolate as the redox active group that exchanges directly electrons with the electrode via the gold nanoparticles. The formal potential E ° ′ of AaeAPO in the gold nanoparticles-chitosan film was estimated to be -(286 ± 9) mV at pH 7.0. The heterogeneous electron transfer rate constant (ks) increases from 3.7 in the scan rate range from 0.2 to 3.0 V s-1 and level off at 63.7 s-1. Furthermore, the peroxide-dependent hydroxylation of aromatic compounds was applied to develop a sensor for naphthalene and nitrophenol. The amperometric measurements of naphthalene are based on the indication of H2O2 consumption. For the chitosan-embedded gold nanoparticle system, the linear range extends from 4 to 40 μM naphthalene with a detection limit of 4.0 μM (S/N = 3) and repeatability of 5.7\% for 40 μM naphthalene.}, language = {en} } @misc{PengWollenbergerHofrichteretal., author = {Peng, Lei and Wollenberger, Ulla and Hofrichter, Martin and Ullrich, Ren{\´e} and Scheibner, Katrin and Scheller, Frieder W.}, title = {Bioelectrocatalytic properties of Agrocybe aegerita peroxygenase}, series = {Electrochimica Acta}, volume = {55}, journal = {Electrochimica Acta}, number = {27}, issn = {0013-4686}, doi = {10.1016/j.electacta.2009.12.065}, pages = {7809 -- 7813}, abstract = {A biosensor for detecting the aromatic substance 4-nitrophenol based on Agrocybe aegerita peroxygenase (AaP) immobilized with chitosan-stabilized gold nanoparticles is presented here. This biosensor measures the enzymatic product of 4-nitrophenol peroxygenation, 4-nitrocatechol, which is electrochemically detected in the presence of hydrogen peroxide. Cyclic voltammetry and amperometry were used to characterize the proposed biosensor. The linear range of the AaP biosensor for the detection of 4-nitrophenol was between 10 and 30 μM with a detection limit of 0.2 μM (based on the S/N = 3). The catalytic property of AaP to oxidize 4-nitrophenol was compared with two other heme proteins, a camphor-hydroxylating cytochrome P450 monooxygenase (P450cam, CYP101) and horseradish peroxidase (HRP). The results revealed that only AaP is capable of catalyzing the hydroxylation of 4-nitrophenol into 4-nitrocatechol. Consequently, AaP could be a particularly potent biocatalyst that may fill the gap between cytochrome P450s and common heme peroxidases.}, language = {en} }