The Electrochenmistry Of Rusticyanin

Direct electrochemistry of redox enzymes and proteins has aroused great interest in biological and bioelectrochemical fields. Studies on direct electrochemistry of redox proteins/enzymes can be used to extract essential physicochemical data concerning the kinetics and energetics of protein redox reactions, provide mechanistic studies of electron exchange among proteins/ enzymes in biological systems. Moreover, direct electron transfer between immobilized enzyme and underlying electrode can establish a foundation for fabricating new kinds of biosensors, biofuel cells, bioreactors.Rusticyanin is a small blue copper protein with extreme acid stability and redox potential. The protein is thought to be a principal component in the iron respiratory electron transport chain of A.ferrooxidans, and its function is proposed to mediate electron transfer between a cytochrome C and the terminal cytochrome C oxidase. Currently, many biological methods are applied to analysis gene composition and structure of the protein, but electrochemical methods are reported rarely. Firstly, the dissertation study on construct ZnS quantum dots (QDs) modified Au electrode with rusticyanin, then research on the electrochemical behaviors of the rusticyanin on the modified electrodes.We extract the rusticyanin from the positive clones of the E.coil strains and purify the rusticyanin using Hitrap chealting HP and SDS-PAGE. Then we synthesize the ZnS QDs with free carboxyl groups in the aqueous phase, which is modified to the L-Cys/Au electrodes. At last we combine the rusticyanin to construct the c/ZnS QDs/L-Cys/Au electrodes.Firstly the dissertation studies on the influence of the rusticyanin/ZnS QDs/L-Cys/Au electrode's electrochemical behaviors under the different factors using cyclic voltammetry. The results show that:rusticyanin has reductibility within a certain range of temperature(19℃-43℃); In the range, the reductibility of the rusticyanin increase with the temperature increase. But above the 43℃, the reductibility falls with the temperature's increasing.Secondly we set several pH to observe the influence of behaviors of the rusticyanin/ZnS-QDs/L-Cys/Au electrodes. We find that the pH has remarkable infection on the behaviors of the rusticyanin/ZnS-QDs/L-Cys/Au electrodes, the reductibility increase with the pH increase.Thirdly, study on the influences of different ions to the rusticyanin/ZnS-QDs/L-Cys/Au electrodes, we find that:while ferrous ions concentration in the range of 0.02-0.05 mol/L, with the concentration of ferrous ions increase, the reduction peak current of the electrode increases linearly, at the same time the oxidation peak current increases similarly; with the concentration of copper ions in the range of 0.01-0.04 mol/L, the electrochemical behaviors of the rusticyanin/ZnS-QDs/L-Cys/Au electrodes looks similarly. When the concentration of the copper ions reach to 0.05mol/L, we induce the the copper in the rusticyanin and the Met148 form a complex. Otherwise, we discover copper ions have more influence to the rusticyanin/ZnS-QDs/L-Cys/Au electrodes than the ferrous ions.