Hypochlorite-induced oxidative modification of fibrinogen

Fibrinogen (FG) is a protein that plays a key role in the hemostasis system and is most susceptible to oxidative modification compared to other plasma proteins. FG undergoes post-translational modifications that can potentially disrupt its structure and function.For the first time, using high resolution mass spectrometry (HPLC/MS/MS), the consequences of hypochlorite (HOCl)- induced FG oxidation were studied, and a list of FG amino acid residue oxidatively modifications. Samples of nonoxidized and treated with 50 μM HOCL fibrinogen were analyzed by mass spectrometry and it was found that many amino acid residues localized in all three polypeptide chains and the main structural elements of fibrinogen, with the exception of the E region, are involved in oxidation.Thus, the amino acid residues localized in the E region, which are involved in thrombin binding, were not subject to oxidative modification, which indicates the preservation of the thrombin-binding sites of the fibrinogen molecule during oxidation. The αС region contains the largest number of oxidizing sites, which confirms the hypothesis that this region can serve as a trap for reactive oxygen species (ROS) molecules.