Multi-step reduction of nitric oxide by cytochrome c entrapped in phosphatidylcholine films

By entrapping cytochrome c (Cyt c) in phosphatidylcholine (PC) film, we have obtained the direct electrochemistry of the protein. Meanwhile, the catalytic reduction of nitric oxide (NO) has been investigated. Besides the pair of peaks corresponding to the redox reactions of Cyt c, two new cathodic peaks can be observed after the addition of NO into the test solution. One, located at −0.510 V, is proposed to come from the formation of hydroxylamine. The other, at −0.690 V, is assigned to the electrochemical reduction of NO. These observations are very different from the previous reports, because only one peak can be obtained for the other studies. The difference is related to the electron transfer rate and the escape rate of the products in the NO reduction process. This study might bring clearer insight into the reduction mechanism of NO.