Aerobic Decomposition of a Dimethylthiourea Nitrosyl Iron Complex in the Presence of Albimin and Glutathione
摘要
Nitrosyl iron complexes (NICs) are natural depots of NO. NICs are formed by the interaction of endogenous nitric oxide (NO) and non‒heme [2Fe–2S] proteins. Their synthetic analogues are promising compounds in medicines for the treatment of socially significant diseases. In this paper, the effect of bovine serum albumin (BSA) and reduced glutathione (GSH) on the decomposition of a nitrosyl iron complex with N,N'-dimethylthiourea ligands [Fe(SC(NHCH3)2)2(NO)2]BF4 (complex 1) under aerobic conditions are studied. In the absorption spectra complex 1 in the presence of albumin a wide band appears at 370–410 nm, which indicates the coordination of the aerobic decay product of the complex in the hydrophobic pocket of the protein with Cys34 and His39. The quenching of albumin’s intrinsic fluorescence during titration with complex 1 is studied by fluorescence spectroscopy. The Stern–Volmer constant K = (2.3 ± 0.2) × 105 М–1 and the Förster radius 22.4 Å are calculated. The UV-spectrum of complex 1 in the presence of GSH has two peaks at 312 and 363 nm, characteristic of glutathione binuclear NICs.