Features of the decomposition of thiosulfate nitrosyl iron complex in the presence of hemoglobin and cytochrome c

Nitrosyl complexes of non-heme iron (NICs) are the depot of nitric monoxide (NO) in the body. They nitrosylate heme-containing proteins in the process of decomposition. In this work, we studied the interaction of the thiosulfate complex Na-2[Fe-2(S2O3)(2)(NO)(4)]& sdot;4H(2)O (complex 1), as a promising drug agent, with hemoglobin and cytochrome c. It was found that complex 1 and its decomposition products are adsorbed on the surface of oxyhemoglobin, leading to longer NO generation compared to an aqueous buffer solution. In the system with metHb, the accumulation of the product (nitrosyl hemoglobin) occurs only under anaerobic conditions. The article also presents experimental data on the nitrosylation of ferro- and ferricytochrome c (cyt c(2+) and cyt c(3+), respectively) in the presence of complex 1. Cyt c(2+) forms the product (NO)cyt c(2+), which serves as the "depot" form of NO. This protein has a lesser stabilizing effect on complex 1 compared to hemoglobin. In the system with cyt c(3+), nitrosylation of protein occurs during mixing, due to the presence of an oxidizing agent K-3[Fe(CN)(6)].