利用紫茉莉中4,5-多巴雙加氧酶之生物感測器選擇性偵測左旋多巴及二價銅離子

左旋多巴為生物體內合成多巴胺的前驅物，並且為目前治療帕金森氏症最有效的藥物，因此檢測左旋多巴是一項重要的議題。在本實驗中，我們開發了一種新型的比色法生物感測器，左旋多巴在紫茉莉之4,5-多巴雙加氧酶 (MjDOD) 催化下生成黃色的甜菜醛胺酸 (具有430 nm特徵吸收峰，為甜菜色素之前驅物)，以此作為訊號來源，針對左旋多巴濃度能夠有良好的相關係數以及偵測極限 (2.8M)。本篇所開發出的系統對於偵測左旋多巴具有簡單、快速、靈敏且選擇性高等優點，同時對其他兒茶酚胺類化合物的干擾保持高度專一性，並且也利用標準添加法成功地應用於真實樣品胎牛血清中，得到良好的準確度。此外，以甜菜醛胺酸為起始物，加入一級胺類進行縮合反應生成甜菜色素，具有紅色螢光，並以其做為小分子螢光探針，能夠選擇性偵測水中的二價銅離子，並分別透過吸收與放射光譜與質譜等完成其性質鑑定，我們也成功將此系統應用於馬血清及人工尿液中，證明其穩定性和適用性。

關鍵字

左旋多巴；甜菜醛胺酸； 4,5-多巴雙加氧酶；比色法生物感測器；螢光感測器；銅離子

並列摘要

L-DOPA, a precursor for the biosynthesis of dopamine, is currently the most effective drug for the treatment of Parkinson's disease. Therefore, it is an important research topic to develop a quantitative method to accurately estimate the level of L-DOPA. In this study, we developed a novel colorimetric biosensor for selectively detecting of L-DOPA. L-DOPA can be catalyzed by Mirabilis jalapa dopa-dioxygenase and converted into betalamic acid (a precursor of betaxanthin and has a λmax absorption at 430 nm), which is yellow color and serves as the signal output. The detection of limit for L-DOPA was 2.8 μM. The proposed system is simple, rapid, sensitive, and selective to L-DOPA while remaining robust to interference from other catecholamines. It is successfully applied to the determination of L-DOPA in spiked fetal bovine serum samples. In addition, betalamic acid is used as a starting material, and the primary amine is added to carry out the condensation reaction to produce betaxanthin, which exhibits red fluorescence. Betaxanthin based fluorescent sensor was prepared and characterized by absorption, emission spectrum, and mass spectrometry. The proposed system can selectively detect copper(II) ion in water. We also validate the performance of this system in artificial urine and equine serum, confirming its robustness and applicability.