Chloroperoxidase Catalytic Synthesis Of Aniline Functional Polymers

Chloroperoxidase (CPO) is now considered as the most widespread activity enzyme in heme peroxidase family. It has catalytic function of peroxidase, catalase and cytochrome P-450 possess. It can adapt to extensive substrate.CPO active site structure is rather special. The "proximal" of hemoglobin is the thiol sulfur atom of cysteine (Cys29) as the fifth axial ligand of iron, and in this position of other peroxidases occupies histidine imidazole nitrogen atoms except P-450; CPO hemoglobin "remote" is hydrophilic environment, and glutamic acid (Glu183) acts as acid-base catalyst composition instead of histidine; while the substrate does not access to the hemoglobin edge directly. It needs to set a hydrophobic channel, with an opening in the top of hemoglobin to connect with this channel, so that the substrate can get close to the CPO catalyst intermediates compoundⅠof Fe4+=O·+. Although many activities of CPO has continued to be excavated, but its research in polymer synthesis has reported rarely. Are features of the substrate channel of CPO active site limited its application in polymer synthesis? This paper used o-phenylenediamine (OPD) and p-phenylenedi-amine (PPD) as the model substrate to study the CPO enzyme-catalyzed polymerization of aniline compounds. The main results were as follows:(1) CPO catalyzed H2O2 oxidizeding polymerization of OPD:Nuclear Magnetic Resonance (NMR), Ultraviolet-Visible (UV-vis) and Fourier Transform Infrared (FT-IR) representatives confirmed that the product double-o-phenylenediamine polymers of this enzymatic reaction was 2,3-diamino phenazine (DAP); enzymatic reaction was free radical process, mainly controlled by the stability of CPO, the amount of enzyme and so on; the introduction of imidazolium ionic liquids (ILS) as the co-solvent could improve the yield, and enzyme kinetic analysis showed that the CPO on the substrate affinity and the specificity of substrate recognition in the ionic liquids could be improved. The DAP yield was 81.16% under the optimum condition.2,3-diaminophenazine has good fluorescence properties, so the OPD-H2O2-CPO reaction is expected for the fluorescence enzyme immunoassay.(2) CPO catalyzed H2O2 oxidizeding polymerization of PPD:The characterization of the structure and performance of the product showed polymer of CPO-catalyzed PPD was polyaniline (PANI) which had low polymerization of product but had electrical conductivity, good electrochemical activity and thermal stability. The results of UV-visible Spectral Scanning, CV patterns, Electron Microscope Scanning, Thermal Gravimetric Analysis and Conductivity Measurement and so on showed that, by doping small molecules and the introduction of templates, polyaniline electrochemical activity, electrical conductivity, thermal stability improved significantly than eigenstate polyaniline. After filtering, high sodium chlorate as the doping agent, with MPPD:MSodium Perchlorate=1:1, the product had obvious lamellar structure, the electrochemical activity of the best, with strong reversible redox capacity; with polystyrene sulfonate (SPS) as the template thermal stability of polyaniline was the best, with the conductivity maximum. Combination polyaniline and SPS also could greatly enhance the water solubility of polyaniline, broaden its scope of application; the electrochemical activity of product and the pH value of reaction system were highly correlated, and the best pH was 5.5. But in the ionic liquid co-solvent, the performance of enzymatic synthesis of polyaniline was not ideal.