Ibrahim M S, Kamal M M, Temerk Y M
Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt.
Anal Bioanal Chem. 2003 Apr;375(8):1024-30. doi: 10.1007/s00216-003-1827-z. Epub 2003 Mar 19.
The determination of the interaction between lumichrome (LC), one of the products of decomposition of the biologically important flavins, and calf thymus double-stranded DNA was performed by using cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV) in connection with a hanging mercury drop electrode (HMDE) or glassy carbon electrode (GCE). The nature of the process taking place at both electrode surfaces was clarified. It was found that the addition of DNA to a buffered LC solution results in the decrease of redox peak currents with changes in the peak potentials at both electrodes. We assume that LC interacting with DNA produces an electrochemically inactive supramolecular complex via intercalation. There was a difference between the electrochemical parameters determined at the HMDE and those at the GCE. The binding constants ( K) of the LC-DNA complex at HMDE and GCE were determined through the changes of peak currents and their values at the 10(5) level and 10(4) level with each nucleotide residue of DNA binding one LC molecule, respectively. Furthermore, the calibration graph for the determination of DNA was obtained by the decrease in the DPSV peak current of LC in the presence of DNA. Different variables, such as the concentration of LC, the accumulation time and solution conditions, were studied and optimised to maximize the sensitivity; in addition, the detection limit and the reproducibility were determined.
通过使用循环伏安法（CV）和差分脉冲溶出伏安法（DPSV）并结合悬汞滴电极（HMDE）或玻碳电极（GCE），对生物重要黄素分解产物之一的光色素（LC）与小牛胸腺双链DNA之间的相互作用进行了测定。阐明了在两个电极表面发生的过程的性质。发现将DNA添加到缓冲的LC溶液中会导致氧化还原峰电流降低，同时两个电极的峰电位也会发生变化。我们假设与DNA相互作用的LC通过嵌入产生一种电化学惰性的超分子复合物。在HMDE和GCE上测定的电化学参数存在差异。通过峰电流的变化分别测定了HMDE和GCE上LC-DNA复合物的结合常数（K），其值分别在10⁵水平和10⁴水平，即每个DNA核苷酸残基结合一个LC分子。此外，通过在存在DNA的情况下LC的DPSV峰电流降低获得了用于测定DNA的校准曲线。研究并优化了不同变量，如LC的浓度、积累时间和溶液条件，以最大化灵敏度；此外，还确定了检测限和重现性。
