合成胜肽鏈中保護胺基酸之溶解度參數測定

Solubility parameter determination for protected amino acids in synthetic peptides

鍾瑩(Ying Zhong)

指導教授 ： 阮若區 ； 陳文逸

國立中央大學/工學院/化學工程與材料工程學系/碩士(2011年)

摘要

近年來胜肽(peptide)藥物廣泛地應用在疾病治療方面，因此胜肽的合成與純化扮演相當重要的角色。胜肽合成技術於近數十年間已日趨純熟，其中以固相合成(Solid-phase synthesis)為最大宗，但往往胜肽鏈的增長與結構效應大幅降低了合成的產率。因此，期望能以固相分段合成短片段之胜肽，再於液相中接合，來改善低產率之問題，但由於固相合成過程中有許多胺基酸具有疏水的保護基團，所以我們不僅要考慮接點問題，更要找到合適的溶劑以利接合。故本研究著重於疏水胺基酸與保護胺基酸溶解度參數之求得，並進一步地估算胜肽的溶解度參數，根據溶解度參數理論來尋找合適之溶劑。本研究設計了21條胜肽(Fmoc-Gly-Phe~X~Phe-Gly-OH, ~X~ 位置分別放置20個胺基酸，另外未放置的為控制組)，以逆相層析(Reverse-phase chromatography)之方式求得胜肽之溶解度參數，進一步的計算疏水胺基酸與保護胺基酸的溶解度參數。與Hoy軟體計算結果之比較顯示，實驗所得之極性(polarity，δp)作用力較大，氫鍵作用力較小(hydrogen bonding，δh)，又與文獻上兩液相分配法量測之疏水性成正相關。此外我們也找一條具保護胺基酸之胜肽來計算其溶解度參數、溶劑之選擇和預測其滯留行為，結果顯示確實精準預測胜肽於何種溶劑條件下可被沖堤。這表示導入溶解度參數之概念於層析系統中，不僅可準確預測具有側鏈保護基團的胜肽之滯留行為，亦可有助於我們找到合適的溶劑。

關鍵字

溶劑選擇 ； 胜肽純化 ； 胜肽合成 ； 溶解度參數

並列摘要

In the past few decades, with the widely application of the peptide drug in medical treatment, the peptide synthesis and purification play important roles. The technology development of liquid-phase and solid-phase synthesis becomes mature state. However, there exists a problem that the purification yield decreases with the length of peptide chain or conformation effect. Therefore, we propose a new idea to improve the yield. First, use the solid-phase synthesis method to obtain part of the long-chain peptide. And after purifying these fragments, operate the ligation step in liquid phase. In order to find the common solvents for these peptides in the ligation step, we utilize the solubility parameter theory that widely used in polymer-solvent selection to study the hydrophobic and protected amino acids. We use the reverse-phase chromatography to investigate the solubility parameters of the designed 21 model peptides (Fmoc-Gly-Phe-X-Phe-Gly, -X- is replaced by 20 different amino acids), and then do the calculation to obtain the solubility parameters of hydrophobic and protected amino acids. In addition to comparing the results with Hoy software calculated data, the correlation of the experimental partition energy and hydrophobicity from the literature is also to be study. Finally, we take a peptide composed of protected amino acids to estimate its solubility parameters, find the suitable solvents and predict the retention behavior successfully. The result shows that apply the solubility parameter theory in RP-HPLC to study the hydrophobic and protected amino acids can not only do the help in peptide-solvent selection but also prediction the elution conditions.

並列關鍵字

solvent selection ； solubility parameter ； peptide synthesis ； peptide purification

參考文獻

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