Generation and Characterization of SAM Immobilized Enzyme Films in Ionic Liquids

摘要: Abstract : Electrochemical investigations of the heme protein dehaloperoxidase (DHP) were undertaken. Motivation for this work lies in unusual bifunctional nature DHP, a globin-type found marine worm Amphitrite ornata. DHP is monomeric hemoglobin that not only binds and transports dioxygen but features high level peroxidase activity enzymatic detoxification halogenated phenolic compounds such as 2,4,6-tribromophenol. Direct electrochemistry absence mediators was realized both diffusional non-diffusional voltammetric cases using mixed OH/COOH self-assembled monolayer modified electrodes alkanethiolate/gold construction. It appears interacts with anionic via lysine patch situated vicinity edge. Interfacial voltammetry suffers from instability problems have been completely resolved. Accordingly, mediated thin-layer spectroelectrochemistry utilized to characterize Fe(III)/Fe(II) redox thermodynamic properties DHP. The reduction potential at pH 7 determined under anaerobic conditions be +202 mV vs SCE, most positive value any known intracellular globin. This rationalized terms redox-coupled conformational behavior involving distal histidine (H55) by analyzing Gibbs free energy contributions potential. impact enzyme substrate interactions on also characterized gave evidence internal external binding depending upon extent halogen substitution substrate. A cubic cycle proposed accounted changes interactions. Finally, several methionine-86 mutants prepared investigate electron push effect concept activity. first successful installation peroxide-like aspartate-histidine-iron triad into globin achieved (M86D mutant).