Electron transfer reactivity and the catalytic activity of hemoglobin incorporated in dimethylaminoethyl methacrylate film

Abstract

Hemoglobina (Hb) foi incorporada em Dimetilaminoetil metacrilato (DMAEMA), na preparação de um filme e este foi modificado em eletrodo de grafite pirolítico (PG). O espectro de UV-Vis sugeriu que a hemoglobina no filme manteve sua estrutura secundária. Conseqüentemente, foram observados um par de picos voltamétricos cíclicos, estáveis, bem definidos e quasi-reversíveis, com o potencial formal de -206 mV (vs. eletrodo de calomelano saturado), característico do par redox Fe(III)/Fe(II) do grupo heme da proteína. A constante de velocidade aparente da transferência de elétron heterogênea e outros parâmetros eletroquímicos foram apresentados. A atividade catalítica da Hb em filmes de DMAEMA, frente ao peróxido de hidrogênio, foi também investigada.Hemoglobin (Hb) was incorporated in dimethylaminoethyl methacrylate (DMAEMA) to form a film and the film was modified on pyrolytic graphite (PG) electrode. UV-Vis spectra suggested that Hb in the film could keep its secondary structure. Consequently, a pair of stable, well-defined, and quasi-reversible cyclic voltammetric peaks could be observed with the formal potential at -206 mV (vs. saturated calomel electrode), characteristic of heme Fe(III)/Fe(II) redox couple of the protein.The apparent heterogeneous electron transfer rate constant and other electrochemical parameters were presented. The catalytic activity of Hb in DMAEMA films toward hydrogen peroxide was also investigated.Keywords: direct electrochemistry, hemoglobin, dimethylaminoethyl methacrylate, electrocatalysis IntroductionStudies on the direct electron transfer between proteins or enzymes and electrode surfaces have showed great significance both in theory and practice. [1][2][3][4] However, methods to achieve the direct electron transfer reactions are still limited. Recently, studies have revealed that by incorporating proteins or enzymes in some kinds of films, direct electrochemistry of the macromolecules might be achieved. Lots of laboratories and ours have examined many kinds of film materials to incorporate proteins or enzymes and to facilitate the electron transfer reactivity. However, there is still a lot of work to do to try some other materials.Our previous work has showed that quite a few cationic compounds and their polymers can form fine film structure on electrodes, which is suitable for studying the direct electrochemistry and electrocatalytic behavior of proteins or enzymes. Dimethylaminoethyl methacrylate (DMAEMA) is a colorless, transparent and liquid cationic compound, which can be dissolved in water and many organic solvents, such as ester, ketone, alcohol, ether, hydrocarbon, chlorohydrocarbon, with an amino-like smell. It is an amino-alkaline molecule with a tri-amino, an ester group and unsaturated double-bonds. The tri-amino group can react with acids or alkylating agents such as chloromethane to form salts or quaternary ammonium salts and the ester group can experience hydrolysis or transesterification, while the unsaturated double-bond can undergo addition, polymerization or combin...

Construction of a quaternary ammonium salt platform with different alkyl groups for antibacterial and biosensor applications

“…Previous research has shown that quaternary ammonium salt monomers with various chain lengths can be synthesized and processed. In particular, Zhou et al 24 considered DM as a suitable biomaterial for performing direct electrochemistry of proteins because its characteristics [25][26][27] such as its biocompatibility, [28][29][30] high hydrophilicity, non-toxicity, and low cost. In addition, there are some reports in the literature in which DM can catalyze redox processes, creating a base for future electrochemical sensors.…”

Electrochemical Biosensor Based on Horseradish Peroxidase and Black Phosphorene Quantum Dot Modified Electrode

“…The k s value is larger than that of HRP on Nafion/HRP/AuNTs/CILE (1.01 s −1 ) [ 47 ], Nafion/HRP/Co 3 O 4 /CILE (0.94 s −1 ) [ 48 ], and HRP/nano-Ni-SnO 2 /GCE (1.10 s −1 ) [ 49 ], indicating that the existence of BPQDs played an important role for the fast electron transfer between HRP and the electrode surface. The average surface concentration (Γ*) of electroactive HRP on the modified electrode was calculated based on the equation Q = nFAΓ* [ 50 ]. The value of Γ* was estimated to be 3.54×10 −9 mol/cm 2 , and the total amount of HRP on the modified electrode interface was 2.98×10 −8 mol/cm 2 , which accounted for 11.88% of HRP molecules on the electrode surface taking part in the electrode reaction.…”

Electron transfer and interfacial behavior of redox proteins

“…Some non-ionic surfactants are found to preserve the functional state of proteins and to accelerate ET in the supramolecular complexes [68,69]. Therefore, various surfactants, e.g., Triton X-100 [70], polysorbate-20 (Tween 20) [71], dimethyldioctadecyl ammonium bromide (DOAB) [72], and dimethylaminoethyl methacrylate (DMAEMA) [73], have been employed to entrap Hb onto PGE surface in this lab.…”