Direct electrochemistry of myoglobin based on DNA accumulation on carbon ionic liquid electrode

Poly-anionic deoxyribonucleic acid (DNA) was accumulated oil the positively charged surface of carbon ionic liquid electrode (CILE) with N-butylpyridinium hexafluorophosphate (BPPF6) as binder, and then myoglobin (Mb) was immobilized onto the DNA film by electrostatic interaction to form Mb/DNA/CILE electrode. The direct electrochemistry of Mb was then investigated in detail. A pair of well-defined, quasi-reversible cyclic voltammetric peaks of Mb was obtained with the formal potentials (E-0t) at -0.304 V (vs. SCE) in phosphate buffer solution (PBS, pH 7.0). The Mb/DNA/CILE electrode showed excellent electrocatalytic activity to H2O2 and trichloroacetic acid (TCA) in the range of 1.0-160 mu mol/L and 0.5-40.0 mmol/L, respectively. The apparent Michaelis-Menten constants (K-M) toward H2O2 and TCA were calculated as 0.42 and 0.82 mmol/L. So, the DNA/CILE had potential to study other proteins. (c) 2009 Published by Elsevier B.V.