Modulation of Iron Catalytic Activity to Dopamine Oxidation through Additional Iron Ligation

作者：La Ming^*; Chen Chang Dong; Li He; Yang Cheng Ye

来源：International Journal of Electrochemical Science, 2014, 9(12): 6870-6879.

• dopamine
• iron
• electrochemistry
• nitrilotriacetic acid
• catalytic activity
• hydrogen peroxide

Parkinson's disease (PD) is characterized by the selective degeneration of dopaminergic cells. This bodes well for the role of dopamine (DA) in the etiology of PD, possibly through the Fe(III) catalyzed production of DA derived neuronal toxins. We investigated how the presence of iron ligation of nitrilotriacetic acid (NTA, a well known tetradentate ligand) affected the catalytic oxidation reaction by electrochemistry and UV-vis spectrophotometer. A relatively stable DA-Fe(III)-NTA ternary complex is identified. The additional ligation by NTA shifted the catecholate-Fe(III) ligand metal charge transfer (LMCT) band to a longer wavelength and caused the change of the redox potentials of both DA and Fe(III) center in the ternary complex. Fe(III)-catalyzed DA oxidation kinetics in the absence and presence of NTA was also studied. Remarkably, the additional ligation by NTA was found to totally reverse the Fe(III) catalytic effect. NTA as a tetradentate ligand together with DA saturates all coordination sites of Fe(III). The inaccessibility of O-2 to the metal center blocks the Fe(III) bridged electron transfer between O-2 and DA. Our findings have a significant biological implication.

• 出版日期2014-12
• 单位平顶山学院