Chen Huei-Yu, Yeh Yi-Chun
Department of Chemistry, National Taiwan Normal University Taiwan
RSC Adv. 2020 Aug 12;10(50):29745-29750. doi: 10.1039/d0ra05581f. eCollection 2020 Aug 10.
The aromatic amino acid tyrosine is an essential precursor for the synthesis of catecholamines, including l-DOPA, tyramine, and dopamine. A number of metabolic disorders have been linked to abnormal tyrosine levels in biological fluids. In this study, we developed an enzyme cascade-triggered colorimetric reaction for the detection of tyrosine, based on the formation of yellow pigment (betalamic acid) and red fluorometric betaxanthin. Tyrosinase converts tyrosine to l-DOPA, and DOPA-dioxygenase catalyzes oxidative cleavage of l-DOPA into betalamic acid. Response is linear for tyrosine from 5 to 100 μM, and the detection limit (LOD) is 2.74 μM. The enzyme cascade reaction was applied to monitor tyrosinase activity and tyrosinase inhibition assays. Lastly, the performance of the proposed biosensor proved successful in the analysis of urine samples without the need for pre-treatment.
芳香族氨基酸酪氨酸是合成儿茶酚胺（包括左旋多巴、酪胺和多巴胺）的必需前体。许多代谢紊乱与生物体液中酪氨酸水平异常有关。在本研究中，我们基于黄色色素（甜菜醛氨酸）和红色荧光甜菜色素的形成，开发了一种酶级联触发的比色反应来检测酪氨酸。酪氨酸酶将酪氨酸转化为左旋多巴，多巴双加氧酶催化左旋多巴氧化裂解为甜菜醛氨酸。对5至100μM的酪氨酸响应呈线性，检测限（LOD）为2.74μM。该酶级联反应应用于监测酪氨酸酶活性和酪氨酸酶抑制试验。最后，所提出的生物传感器在无需预处理的情况下成功用于尿液样本分析。
