金属卟啉MTPPS对NADH氧化的催化作用
Catalytic Oxidation of Reduced Coenzyme NADH by Metalloporphrins MTPPS
摘要
中位-四(对-磺基苯基)卟啉的铁、锰配合物(fETPPS和MnTPPS)用作nAdH氧化的催化剂,均相溶液中的反应动力学用紫外可见光谱测定.结果表明,在除氧的中性溶液中fETPPS和MnTPPS降低了nAdH在玻碳电极上氧化的过电位,过程用EC再生机理解释.在氧饱和的溶液中MTPPS起电子转移中介体的作用促进nAdH氧化,其还原态被O_2氧化而再生.测得fETPPS和nAdH反应的速率常数为3.3MOl--(-1)·l·S--(-1),而MnTPPS和nAdH反应的速率常数约为fETPPS的1/2.讨论了MTPPS作为nAdH仿生氧化催化剂的前景. The metalloporphrins FeTPPS and MnTPPS [ TPPS standing for meso-tetrkis ( p-sulfonatophenyl) porphyrin] , were used as the catalysts for NADH oxidation.The reaction kinetics in solution was measured by UV-vis spectroscopy.It was found that in neutral deoxygenated solution, the presence of FeTPPS or MnTPPS decreases the overpotential of NADH oxidation at a glassy carbon electrode, the processes are explained in terms of EC mechanism.In oxygen-saturated solution, MTPPS as an electron-transfer mediator accelerated NADH oxidation, and reduced MTPPS was regeneraed via chemical oxidation by O2 .The rate constant for the oxidation of NADH by FeTPPS was measured as 3.3mol-1·L·s-1, however, for MnTPPS the rate constant was about a half of that for FeTPPS.The prospects of using MTPPS as biomimitic catalysts for NADH oxidation are discussed .