金属卟啉MTPPS对NADH氧化的催化作用

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。

Catalytic oxidation of reduced coenzyme NADH by metalloporphrins MTPPS

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 O~2. 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.