Direct Electrochemistry of Catalase in Multiwall Carbon Nanotube/dodecyl Trimethylammonium Bromide Film Covered With a Layer of Nafion on a Glassy Carbon Electrode

Direct electrochemistry of catalase (Ct) was achieved by confining the protein within multiwall carbon nanotube (MWCNT)-dodecyltrimethyl ammonium bromide (DTAB) film covered with a layer of Nafion (NF) (MWCNT-DTAB-Ct/NF) on the surface of a glassy carbon electrode (GCE). The film exhibited a pair of well-defined quasi-reversible cyclic voltammetric peaks corresponding to the Fe(III)/Fe(II) redox couple in the active site of Ct with a formal potential (Eº΄) = -0.279 V vs. Ag/AgCl, in 50 mM phosphate buffer solution at pH 7.0. Apparent heterogeneous electron transfer rate constant (10.71±0.34 s-1) and charge-transfer coefficient (0.49) were estimated by Laviron’s model. The process of catalytically reducing hydrogen peroxide by the MWCNT-DTAB-Ct/NF film modified electrode was also explored.