以光譜法探討根皮素與胰島素之相互作用

Interaction Between Phloretin and Insulin : A Spectroscopic Study

吳仲文(Zhong-Wen Wu)

指導教授 ： 錢偉鈞

朝陽科技大學/理工學院/應用化學系/碩士(2020年)

摘要

第二型糖尿病患者雖然有能力製造與分泌胰島素，但因胰島素抗性與胰島素分泌量不足導致身體無法有效的利用。文獻證實根皮素具有改善肝臟損傷與改善胰島素抗性之作用。本研究透過光譜法研究胰島素與根皮素之相互作用，試圖探討根皮素改善胰島素抗性的可能機制。透過紫外/可見光光譜結果顯示當根皮素導入胰島素溶液中時，引發胰島素的紫外光吸收產生增色效應及藍位移。螢光光譜實驗則顯示胰島素之螢光強度會隨著添加的根皮素濃度提高而降低，並產生紅位移。這兩種光譜實驗結果證實胰島素與根皮素兩者間具有相互作用並形成複合物。螢光淬熄實驗結果顯示，在288K至308K溫度範圍內，根皮素與胰島素之結合常數Ka值均達1.5×107 M-1以上，所得之熱力學參數熵及焓皆為負數，可判定氫鍵應為兩者之主要作用機制。所得之自由能為-43.65 kJ/mol，顯示兩分子間之作用為一自發反應。根皮素對胰島素之淬熄曲線回歸結果顯示根皮素對胰島素螢光基團除了造成動態淬熄外，同時也伴隨靜態淬熄之效應，顯示根皮素誘導胰島素產生區域性構型變化之可能。圓二色光譜結果呈現根皮素的添加誘導胰島素α-helix構型含量增加。本研究結果顯示根皮素對胰島素中α-helix結構構型的穩定與增強應與根皮素具有改善胰島素抗性之現象有關。

關鍵字

胰島素 ； 根皮素 ； 複合物 ； 螢光淬熄 ； 圓二色光譜

並列摘要

Type 2 diabetes accounts for the fact that although diabetic patients have the ability to make insulin(INS), the body cannot effectively use it due to insufficient INS resistance and INS secretion. In this study, the interaction between INS and Phloretin(PHL) was studied by spectrometry. The results of UV/Vis and fluorescence spectroscopy show that when PHL is introduced into the INS solution, it will cause a hyperchromic effect, a decrease in fluorescence intensity and a shift, confirming that both INS and PHL interact and form a complex. According to the calculation of the fluorescence quenching experiment, the binding constant Ka, the quenching constant Ksv and the quenching rate constant kq can be obtained. Fluorescence quenching test results show that in the temperature range of 288K to 308K, the Ka value of PHL and INS are both above 1.5×107 M-1. The obtained thermodynamic parameters ∆H and ∆S are both negative numbers, and it can be determined that hydrogen bonding should be the main mechanism of action of both. The resulting free energy is -43.65 kJ/mol, indicating that the interaction between the two molecules is a spontaneous reaction. The results of circular dichroism spectrum showed that the addition of PHL induced an increase in the content of INS α-helix configuration. The results of this study indicate that the stability and enhancement of the structure of α-helix in INS by PHL should be related to the phenomenon that PHL improves INS resistance.

並列關鍵字

Insulin ； Phloretin ； Complex ； Fluorescence quenching ； CD

參考文獻

參考文獻

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