Nitrite reduction mediated by heme models. Routes to NO and HNO

摘要: The water-soluble ferriheme model FeIII(TPPS) mediates oxygen atom transfer from inorganic nitrite to a phosphine (tppts), dimethyl sulfide, and the biological thiols cysteine (CysSH) glutathione (GSH). products with latter reductant are respective sulfenic acids CysS(O)H GS(O)H, although these reactive intermediates rapidly trapped by reaction excess thiol. nitrosyl complex FeII(TPPS)(NO) is dominant iron species while substrate present. However, in slightly acidic media (pH ≈ 6), system does not terminate at this very stable ferrous nitrosyl. Instead, it displays matrix of redox transformations linking spontaneous regeneration formation both N2O NO. Electrochemical sensor trapping experiments demonstrate that HNO (nitroxyl) formed, least when tppts reductant. likely predecessor N2O. A key pathway NO reduction FeII(TPPS), kinetics ir...