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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 MP-11-AuNP-CH/GCE in different buffer concentrations at pH 7.
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biosensors-02-00189-f003: Cyclic voltammograms of MP-11-AuNP-CH/GCE in different buffer concentrations at pH 7.

Mentions: Furthermore, we investigated the DET of MP-11 at the AuNP-CH modified GC electrodes and elucidated the effect of ionic strength of the measuring buffer solutions. MP-11 displayed in the cyclic voltammograms a pair of quasi-reversible redox peaks at all ionic strength, whilst in the absence of MP-11 the AuNP-CH modified GCE did not show a redox signal (not shown). As shown in Figure 3, the peak currents decrease with increasing ionic strength between 2.5 mM to 100 mM at pH 7. The formal potential of MP-11 in 10 mM PB, at pH 7 was calculated to be −335.75 mV at the scan rate of 100 mV/s.


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 MP-11-AuNP-CH/GCE in different buffer concentrations at pH 7.
© Copyright Policy
Related In: Results  -  Collection

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

biosensors-02-00189-f003: Cyclic voltammograms of MP-11-AuNP-CH/GCE in different buffer concentrations at pH 7.
Mentions: Furthermore, we investigated the DET of MP-11 at the AuNP-CH modified GC electrodes and elucidated the effect of ionic strength of the measuring buffer solutions. MP-11 displayed in the cyclic voltammograms a pair of quasi-reversible redox peaks at all ionic strength, whilst in the absence of MP-11 the AuNP-CH modified GCE did not show a redox signal (not shown). As shown in Figure 3, the peak currents decrease with increasing ionic strength between 2.5 mM to 100 mM at pH 7. The formal potential of MP-11 in 10 mM PB, at pH 7 was calculated to be −335.75 mV at the scan rate of 100 mV/s.

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.