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Bioelectrochemical Characterization of Horseradish and Soybean Peroxidases
Author(s) -
Frasconi Marco,
Favero Gabriele,
Tortolini Cristina,
Mazzei Franco
Publication year - 2009
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200900208
Subject(s) - horseradish peroxidase , peroxidase , chemistry , substrate (aquarium) , hydrogen peroxide , cyclic voltammetry , electron transfer , redox , catalysis , voltammetry , biosensor , electrochemistry , combinatorial chemistry , inorganic chemistry , photochemistry , electrode , enzyme , organic chemistry , biochemistry , oceanography , geology
Heme peroxidase are ubiquitous enzymes catalyzing the oxidation of a broad range of substrates by hydrogen peroxide. In this paper the bioelectrochemical characterization of horseradish peroxidase (HRP) and soybean peroxidase (SBP), belonging to class III of the plant peroxidase superfamily, was studied. The homogeneous reactions between peroxidases and some common redox mediators in the presence of hydrogen peroxide have been carried out by cyclic voltammetry. The electrochemical characterization of the reactions involving enzyme, substrate and mediators concentrations allowed us to calculate the kinetic parameters for the substrate–enzyme reaction ( K MS ) and for the redox mediator–enzyme reaction ( K MM ). A full characterization of the direct electron transfer kinetic parameters between the electrode and enzyme active site was also performed by opportunely modeling data obtained from cyclic voltammetry and square wave voltammetry experiments. The experimental data obtained with immobilized peroxidases show enhanced direct electron transfer and excellent electrocatalytical performance for H 2 O 2 . Despite the structural similarities and common catalytic cycle, HRP and SBP exhibit differences in their substrate affinity and catalytic efficiency. Basing on our results, it can be concluded that peroxidase from soybean represents an interesting alternative to the classical and largely employed one obtained from horseradish as biorecognition element of electrochemical mediated biosensors.