Photochemical reduction of cytochrome c by a 1,4,5,8-naphthalenediimide radical anion |
| |
Authors: | Campos Ivana B Nantes Iseli L Politi Mario J Brochsztain Sergio |
| |
Institution: | Centro Interdisciplinar de Investiga??o Bioquímica, Universidade de Mogi das Cruzes, Mogi das Cruzes, SP, Brazil. |
| |
Abstract: | Steady-state UV irradiation of aqueous solutions containing cytochrome c (cyt c) and N,N'-bis(2-phosphonoethyl)-1,4,5,8-naphthalenediimide (BPNDI), a water-soluble aromatic imide, resulted in the reduction of the heme iron from the Fe(III) to the Fe(II) oxidation state. The reaction kinetics were followed by the increase of the ferrocytochrome c absorbance band at 549 nm. The rate of the photochemical reaction was pH dependent, reaching its maximum values over the pH range 4-7. Addition of electrolyte (NaCl) at pH 5 resulted in a decrease in the reaction rate, as expected for reactions between oppositely charged species. Flash photolysis studies revealed that the actual reductant in the reaction was a photogenerated BPNDI radical anion, which transferred an electron to the cyt c heme iron. The participation of imide radicals in the process was confirmed by the ready reduction of cyt c by BPNDI radicals chemically generated with sodium dithionite. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|