Rhee Hyun-Woo, Choi So Jung, Yoo Sang Ho, Jang Yong Oh, Park Hun Hee, Pinto Rosa María, Cameselle José Carlos, Sandoval Francisco J, Roje Sanja, Han Kyungja, Chung Doo Soo, Suh Junghun, Hong Jong-In
Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea.
J Am Chem Soc. 2009 Jul 29;131(29):10107-12. doi: 10.1021/ja9018012.
Flavins, comprising flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), and riboflavin (RF, vitamin B(2)), play important roles in numerous redox reactions such as those taking place in the electron-transfer chains of mitochondria in all eukaryotes and of plastids in plants. A selective chemosensor for flavins would be useful not only in the investigation of metabolic processes but also in the diagnosis of diseases related to flavins; such a sensor is presently unavailable. Herein, we report the first bifunctional chemosensor (PTZ-DPA) for flavins. PTZ-DPA consists of bis(Zn(2+)-dipicolylamine) and phenothiazine. Bis(Zn(2+)-dipicolylamine) (referred to here as XyDPA) was found to be an excellent catalyst in the conversion of FAD into cyclic FMN (riboflavin 4',5'-cyclic phosphate, cFMN) under physiological conditions, even at pH 7.4 and 27 degrees C, with less than 1 mol % of substrate. Utilizing XyDPA's superior function as an artificial FMN cyclase and phenothiazine as an electron donor able to quench the fluorescence of an isoalloxazine ring, PTZ-DPA enabled selective fluorescent discrimination of flavins (FMN, FAD, and RF): FAD shows ON(+), FMN shows OFF(-), and RF shows NO(0) fluorescence changes upon the addition of PTZ-DPA. With this selective sensing property, PTZ-DPA is applicable to real-time fluorescent monitoring of riboflavin kinase (RF to FMN), alkaline phosphatase (FMN to RF), and FAD synthetase (FMN to FAD).
黄素类物质，包括黄素单核苷酸（FMN）、黄素腺嘌呤二核苷酸（FAD）和核黄素（RF，维生素B2），在众多氧化还原反应中发挥着重要作用，比如在所有真核生物线粒体以及植物质体的电子传递链中发生的反应。一种用于黄素类物质的选择性化学传感器不仅在代谢过程研究中有用，而且在与黄素相关疾病的诊断中也很有用；目前还没有这样的传感器。在此，我们报道了首个用于黄素类物质的双功能化学传感器（PTZ-DPA）。PTZ-DPA由双（Zn(2+)-二吡啶甲胺）和吩噻嗪组成。发现双（Zn(2+)-二吡啶甲胺）（在此称为XyDPA）在生理条件下，即使在pH 7.4和27摄氏度时，以不到1 mol%的底物，能将FAD高效催化转化为环状FMN（核黄素4',5'-环磷酸酯，cFMN）。利用XyDPA作为人工FMN环化酶的卓越功能以及吩噻嗪作为能够淬灭异咯嗪环荧光的电子供体，PTZ-DPA能够对黄素类物质（FMN、FAD和RF）进行选择性荧光识别：加入PTZ-DPA后，FAD显示荧光增强（ON(+)），FMN显示荧光猝灭（OFF(-)），RF显示无荧光变化（NO(0)）。凭借这种选择性传感特性，PTZ-DPA可应用于实时荧光监测核黄素激酶（RF转化为FMN）、碱性磷酸酶（FMN转化为RF）和FAD合成酶（FMN转化为FAD）。
