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Peroxide-dependent analyte conversion by the heme prosthetic group, the heme Peptide "microperoxidase-11" and cytochrome C on chitosan capped gold nanoparticles modified electrodes.

Yarman A, Neumann B, Bosserdt M, Gajovic-Eichelmann N, Scheller FW - Biosensors (Basel) (2012)

Bottom Line: In view of the role ascribed to the peroxidatic activity of degradation products of cytochrome c (cyt c) in the processes of apoptosis, we investigate the catalytic potential of heme and of the cyt c derived heme peptide MP-11 to catalyse the cathodic reduction of hydrogen peroxide and to oxidize aromatic compounds.The electrochemical signal for the peroxide reduction is generated by the redox conversion of the heme group, whilst a reaction product of the substrate oxidation is cathodically reduced in the substrate indication.The peroxidatic activity of cyt c immobilized in the chitosan layer for catechol was found to be below 1 per mill and for p-aminophenol about 3% as compared with that of heme or MP-11.

View Article: PubMed Central - PubMed

Affiliation: Fraunhofer Institute for Biomedical Engineering, IBMT, D-14476 Potsdam, Germany. aysu.yarman@yahoo.de.

ABSTRACT
In view of the role ascribed to the peroxidatic activity of degradation products of cytochrome c (cyt c) in the processes of apoptosis, we investigate the catalytic potential of heme and of the cyt c derived heme peptide MP-11 to catalyse the cathodic reduction of hydrogen peroxide and to oxidize aromatic compounds. In order to check whether cyt c has an enzymatic activity in the native state where the protein matrix should suppress the inherent peroxidatic activity of its heme prosthetic group, we applied a biocompatible immobilization matrix and very low concentrations of the co-substrate H2O2. The biocatalysts were entrapped on the surface of a glassy carbon electrode in a biocompatible chitosan layer which contained gold nanoparticles. The electrochemical signal for the peroxide reduction is generated by the redox conversion of the heme group, whilst a reaction product of the substrate oxidation is cathodically reduced in the substrate indication. The catalytic efficiency of microperoxidase-11 is sufficient for sensors indicating HRP substrates, e.g., p-aminophenol, paracetamol and catechol, but also the hydroxylation of aniline and dehalogenation of 4-fluoroaniline. The lower limit of detection for p-aminophenol is comparable to previously published papers with different enzyme systems. The peroxidatic activity of cyt c immobilized in the chitosan layer for catechol was found to be below 1 per mill and for p-aminophenol about 3% as compared with that of heme or MP-11.

No MeSH data available.


Cyclic voltammograms of Hemin-AuNP-CH/GCE at different scan rates.
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biosensors-02-00189-f002: Cyclic voltammograms of Hemin-AuNP-CH/GCE at different scan rates.

Mentions: Firstly, DET of hemin on the AuNP-CH modified electrodes was investigated. The cyclic voltammograms of Hemin-AuNP-CH/GCE (Figure 2) exhibit an anodic and a cathodic peak of almost equal heights. Both anodic and cathodic peak currents increase linearly with increasing scan rates between 0.1 and 2 V∙s−1, which indicates a surface-controlled electrode process. The peak separation (ΔEp) is 89 mV at 2∙V∙s−1 which is a characteristic of quasi-reversible systems.


Peroxide-dependent analyte conversion by the heme prosthetic group, the heme Peptide "microperoxidase-11" and cytochrome C on chitosan capped gold nanoparticles modified electrodes.

Yarman A, Neumann B, Bosserdt M, Gajovic-Eichelmann N, Scheller FW - Biosensors (Basel) (2012)

Cyclic voltammograms of Hemin-AuNP-CH/GCE at different scan rates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263574&req=5

biosensors-02-00189-f002: Cyclic voltammograms of Hemin-AuNP-CH/GCE at different scan rates.
Mentions: Firstly, DET of hemin on the AuNP-CH modified electrodes was investigated. The cyclic voltammograms of Hemin-AuNP-CH/GCE (Figure 2) exhibit an anodic and a cathodic peak of almost equal heights. Both anodic and cathodic peak currents increase linearly with increasing scan rates between 0.1 and 2 V∙s−1, which indicates a surface-controlled electrode process. The peak separation (ΔEp) is 89 mV at 2∙V∙s−1 which is a characteristic of quasi-reversible systems.

Bottom Line: In view of the role ascribed to the peroxidatic activity of degradation products of cytochrome c (cyt c) in the processes of apoptosis, we investigate the catalytic potential of heme and of the cyt c derived heme peptide MP-11 to catalyse the cathodic reduction of hydrogen peroxide and to oxidize aromatic compounds.The electrochemical signal for the peroxide reduction is generated by the redox conversion of the heme group, whilst a reaction product of the substrate oxidation is cathodically reduced in the substrate indication.The peroxidatic activity of cyt c immobilized in the chitosan layer for catechol was found to be below 1 per mill and for p-aminophenol about 3% as compared with that of heme or MP-11.

View Article: PubMed Central - PubMed

Affiliation: Fraunhofer Institute for Biomedical Engineering, IBMT, D-14476 Potsdam, Germany. aysu.yarman@yahoo.de.

ABSTRACT
In view of the role ascribed to the peroxidatic activity of degradation products of cytochrome c (cyt c) in the processes of apoptosis, we investigate the catalytic potential of heme and of the cyt c derived heme peptide MP-11 to catalyse the cathodic reduction of hydrogen peroxide and to oxidize aromatic compounds. In order to check whether cyt c has an enzymatic activity in the native state where the protein matrix should suppress the inherent peroxidatic activity of its heme prosthetic group, we applied a biocompatible immobilization matrix and very low concentrations of the co-substrate H2O2. The biocatalysts were entrapped on the surface of a glassy carbon electrode in a biocompatible chitosan layer which contained gold nanoparticles. The electrochemical signal for the peroxide reduction is generated by the redox conversion of the heme group, whilst a reaction product of the substrate oxidation is cathodically reduced in the substrate indication. The catalytic efficiency of microperoxidase-11 is sufficient for sensors indicating HRP substrates, e.g., p-aminophenol, paracetamol and catechol, but also the hydroxylation of aniline and dehalogenation of 4-fluoroaniline. The lower limit of detection for p-aminophenol is comparable to previously published papers with different enzyme systems. The peroxidatic activity of cyt c immobilized in the chitosan layer for catechol was found to be below 1 per mill and for p-aminophenol about 3% as compared with that of heme or MP-11.

No MeSH data available.