The Chloroperoxidase Catalytic Asymmetric Epoxidation And Sulfonation Oxidation

Chloroperoxidase (CPO) has versatile catalytic activities, because of its unique active site structure, such as halogenation, epoxidation, peroxidation, sulfoxidation and alcohols, and so on, so it can be applied widely in organic synthesis, biotransformation, pharmaceuticals, detoxication of environmental pollutants and etc.Because of the bigger consistency of oxidants (H2O2), it will prossess the inhibition to active of CPO. According to reporting, some end alkene at end (such as allylbenzene) causes CPO loses active by suiside. The enzyme catalysizes synthesis chiral compounds by CPO having some difficulties, the yield and enantioselectivity hand been reported is fairly lower at present. Used the epoxidastion of 3-chloropropene and alpha-methyl-sulfide as the model reaction in this work, used the yield and enantioselectivity of the objective outgrowth as the evaluation quota, and have researched the catalytic performance of CPO when added the Ion liquid ([EMIM][Br]. [PMIM][Br]. [BMIM][Br]. [AMIM][Br]),polyhydroxy compounds (glycerol.PEG400. PEG600) and quaternary ammonium salt (TEABr. TPABr. TBABr), and so on as additive, and had discussed the enhance mechanism of CPO on the molecular level by the spectroscopy. The major results as follows:1. The reaction of the epoxidastion of 3-chloropropene was controlled by pH, the kind and dosage of oxidants, the concentration CPO and reaction time, the main product is R-epichlorohydrin. The best effect of enhance on enzyme urge reaction is when indicated that the introduction of ion-liquid ([EMIM][Br]) as co-solvent:the yield and enantioselectivity of (R)-epichlorohydrin reach to 88.8% and 97.1%。The reaction finished in 1h, and CPO consumption was very small.2. The reaction of sulfonation of alkyl sulfide was controlled by pH, the kind and dosage of oxidants, the concentration CPO and reaction time. The introduction of polyol polymeric as addition agent and quaternary ammonium salt can effectively improve the efficiency of the enzyme reaction. The better effect of enhance on enzyme urge reaction is when indicated that the introduction of glycerin, the yield and enantioselectivity of (R)-sulfoxide was 65.5% and 96.3%. But the best effect of enhance on enzyme urge reaction was when indicated that the introduction of quatermary ammonium salt (TEABr) the yield and enantioselectivity of (R)-sulfoxide is 78.2% and 95.4%.UV-vis, fluorescence spectroscopy and circular dichroism (CD) spectromete spectrum assay indicated that the introduction of additive, would intensify the exposure of heme, which made it easier for CPO to bind with the substrate. Moreover, the alpha-helix structure of CPO was improved, which was also favorable for CPO activity and stability.