Department of Chemistry, Faculty of Engineering, Istanbul University , 34320 Istanbul, Turkey.
J Agric Food Chem. 2017 Jul 19;65(28):5821-5830. doi: 10.1021/acs.jafc.7b01649. Epub 2017 Jun 30.
To develop a protein-based biosensor measuring the pro-oxidant activities of phenolic compounds, egg white proteins were precipitated with calcium chloride to obtain an insoluble calcium proteinate complex. This biosensor was used for the determination of Cu(II)-induced pro-oxidant activity of antioxidants such as gallic acid, catechin, epicatechin, quercetin, chlorogenic acid and myricetin, and ascorbic acid. This assay involved the reduction of Cu(II) ions to Cu(I) by antioxidant compounds (simultaneously giving rise to reactive oxygen species) and binding of the formed Cu(I) to the solid biosensor. The protein-bound Cu(I), an indicator of pro-oxidant activity of antioxidants on proteins, was colorimetrically determined at 450 nm with neocuproine (Nc). The method was applied to synthetic mixtures and herbal (sage, green tea, mint, and marjoram) infusions, and its findings were compared to those of a modified carbonyl detection assay. This low-cost biosensor can be prepared in large quantities and used for a long time.
为了开发一种基于蛋白质的生物传感器来测量酚类化合物的促氧化剂活性，用氯化钙沉淀蛋清蛋白，得到不溶性的钙蛋白复合盐。该生物传感器用于测定抗氧化剂（如没食子酸、儿茶素、表儿茶素、槲皮素、绿原酸和杨梅素）和抗坏血酸的 Cu(II)诱导的促氧化剂活性。该测定法涉及抗氧化剂化合物将 Cu(II)离子还原为 Cu(I)（同时产生活性氧），并将形成的 Cu(I)结合到固体生物传感器上。与蛋白结合的 Cu(I)（一种蛋白促氧化剂活性的指示剂）在 450nm 处用新亚铜灵（Nc）比色法测定。该方法应用于合成混合物和草药（鼠尾草、绿茶、薄荷和马郁兰）浸液，并将其结果与改良的羰基检测法进行了比较。这种低成本的生物传感器可以大量制备并长时间使用。
