صدیقه هاشم نیا

In recent years, direct electrochemistry of metalloproteins and metalloenzymes is a subject of immense interest because of its potential application in the study of the redox and electron transfer (ET) properties of biomolecules [1,2].Study on the electrochemical behavior of heme proteins is important for the fundamental understanding of their biological activity. Cytochrome c has been the subject of extensive studies because of its essential function as the electron carrier respiration systems of higher organisms.Nanoparticles have been prepared by a chemical reduction method. The nanosized silver colloids have been characterized using UV-Vis spectroscopy. Colloidal silver modified carbon paste electrodes were prepared by mixing 43-nm-diameter colloidal Ag particles with carbon paste. The modified electrodes displayed a low charging current and a favorable electrochemical response of hexacyanoferrate (III). The direct electrochemical behavior of a horse-heart cytochrome c (cyt.c) adsorbed on this electrode surface is described. It showed a surface-controlled electrode process . Direct electrochemistry of cytochrome c in this paste electrode was easily achieved, and a pair of well-defined quasireversible redox peaks of a heme Fe (III)/Fe (II) couple appeared in pH 7.0 and10.0 mM phosphate buffer solution (PBS). The fabricated modified bioelectrode showed good electrocatalytic ability for reduction of H2O2. The preparation process of the proposed biosensor was convenient, and the resulting biosensor showed high sensitivity, low detection limit, and good stability.