Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
Bioelectrochemistry. 2014 Aug;98:103-8. doi: 10.1016/j.bioelechem.2014.03.010. Epub 2014 Mar 29.
Riboflavin (RF), the primary redox active component of flavin, is involved in many redox processes in biogeochemical systems. Despite of its wide distribution and important roles in environmental remediation, its redox behaviors and reaction mechanisms in hydrophobic sites remain unclear yet. In this study, spectroelectrochemical analysis and density functional theory (DFT) calculation were integrated to explore the redox behaviors of RF in dimethyl sulfoxide (DMSO), which was used to create a hydrophobic environment. Specifically, cyclic voltafluorometry (CVF) and derivative cyclic voltafluorometry (DCVF) were employed to track the RF concentration changing profiles. It was found that the reduction contained a series of proton-coupled electron transfers dependent of potential driving force. In addition to the electron transfer-chemical reaction-electron transfer process, a disproportionation (DISP1) process was also identified to be involved in the reduction. The redox potential and free energy of each step obtained from the DFT calculations further confirmed the mechanisms proposed based on the experimental results. The combination of experimental and theoretical approaches yields a deep insight into the characteristics of RF in environmental remediation and better understanding about the proton-coupled electron transfer mechanisms.
核黄素（RF）是黄素的主要氧化还原活性成分，参与生物地球化学系统中的许多氧化还原过程。尽管 RF 分布广泛，在环境修复中具有重要作用，但它在疏水区的氧化还原行为和反应机制仍不清楚。在这项研究中，我们整合了光谱电化学分析和密度泛函理论（DFT）计算，以探索 RF 在二甲基亚砜（DMSO）中的氧化还原行为，DMSO 用于创建疏水环境。具体而言，我们采用循环伏安荧光法（CVF）和导数循环伏安荧光法（DCVF）来跟踪 RF 浓度变化曲线。结果表明，还原过程包含一系列依赖于电势驱动力的质子耦合电子转移。除了电子转移-化学反应-电子转移过程外，还确定了一个歧化（DISP1）过程也参与了还原。从 DFT 计算获得的每个步骤的氧化还原电位和自由能进一步证实了基于实验结果提出的机制。实验和理论方法的结合深入了解了 RF 在环境修复中的特性，并更好地理解了质子耦合电子转移机制。
