Effects of Mn (II) on peroxynitrite nitrifying fibrinogen.

Fibrinogen is a plasma glycoprotein that is an established cardiovascular risk and it participates in the blood-clotting mechanism. Nitrated fibrinogen has been shown to inhibit platelet aggregation and thrombus formation. However, there are only a few reports relating to the activity and structural changes of nitrified fibrinogen when metal ions are present in the reaction. Mn (II) ion plays an important physiological role in the nervous system and cardiac function. In this study, we use UV-Vis, 3D-fluorescence, SDS-PAGE electrophoresis and Von-Clauss to detect 3-nitrotyrosine (3-NT) production and the activity changes of fibrinogen after nitration and oxidation damage caused by ONOO- in the presence of Mn (II). Results showed that Mn (II) can enhance the production of 3-NT in fibrinogen, promote fluorescence quenching of fibrinogen, and increase the injury to γ and Aα chains of fibrinogen in the presence of peroxynitrite. Consequently, Mn (II) promotes concentration dependent fibrinogen nitrification damage and significantly reduces the biological activity of nitrified fibrinogen.