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|標題:||mPEG-modified HRP for the Synthesis of Fluorescent Naphthol-Based Polymer in organic solvent
|關鍵字:||Horseradish peroxidase;辣跟過氧化酶;modified enzyme;polymerization;organic solvent;酵素聚合反應;化學修飾;有機溶劑||出版社:||化學工程學系||摘要:||
Horseradish peroxidase (HRP) has been chemically modified with the polyethylene glycol monomethyl ethers (MW 5000) yielding derivatives of native HRP with enhanced solubility in organic solvents. Modification didn't cause any loss of activity. Later it was found that these modified enzymes were soluble and active in organic solvents (Acetonitrile and Toluene).
The effects of solvents and reaction condition on the catalytic activity of mPEG-modified HRP were investigated for oxidative polymerization of 2-naphenol in aqueous organic solvents (1,4-dioxane－phosphate buffer and acetonitrile－phosphate buffer) using hydrogen peroxide as an oxidant. In conducting enzymatic polymerization of substituted phenols, the sparingly soluble nature of the monomers in water must be considered. Chain growth in an entirely aqueous medium is not feasible because the even lower solubility of dimmers, trimers and tetramers cause phase separation and precipitation. Naphthol polymerization products were characterized for their relative polarity using reverse－phase HPLC. The effects of concentration of monomers, oxidant and water content on the conversion of monomers have been investigated. The optimal concentration of monomer is 0.045M. Furthermore, the optimal concentration of oxidant is 0.15M. The change of the molecular weight of polymer with varying the water content was found to be related to the molecular clustering in the solution, observed through the difference HPLC for clusters.
本研究利用mPEG（polyethylene glycol monomethyl ethers，MW 5000）修飾辣根過氧化氫酶(Horseradish Peroxidase,HRP)，討論修飾酵素在有機溶劑中的催化活性，並利用修飾後的HRP（mPEG-HRP）催化2-naphthol與氧化劑（H2O2）進行氧化聚合反應，形成poly(2-naphthol)，探討單體轉化率與反應時間、氧化劑添加量、溶劑組成之關係。運用UV-Vis光譜及螢光光譜分析poly(2-naphthol)之形成，高效能液相層析儀分析單體轉化率與分離純化高分子產物。化學修飾後HRP可溶解於Acetonitrile及Toluene中，並具有催化活性。mPEG-HRP溶於 Acetonitrile的活性與未修飾之HRP比較，在25℃時高出35倍，溫度提升至100℃，活性仍然高出6倍。以過氧化氫為氧化劑，利用修飾酵素（mPEG-HRP）催化單體2-naphthol進行聚合反應，其反應十分快速，利用單體的疏水特性進行沉澱分離，當聚合物之聚合度增加時疏水性亦增加，故選用HPLC進行分析。而聚合反應中添加過量氧化劑則會抑制酵素活性，改變反應溶劑組成則影響聚合物之分子量。
|Appears in Collections:||化學工程學系所|
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