PLASMA ASCORBATE PROTECTS COAGULATION-FACTORS AGAINST PHOTOOXIDATION

It has been suggested that proteins, unlike lipids, are not protected against oxidative damage by antioxidants in plasma. We have studied th e effect of photodynamic virus inactivation treatment of fresh human p lasma on coagulation factor activities. Photodynamic treatment generat es singlet oxygen which causes inactivation of fibrinogen and factor W I. Other coagulation factors or anticoagulant proteins are clearly les s affected. We found that there is an inverse correlation between the extent of coagulation factor inactivation during the treatment and the plasma ascorbate concentration, The inactivation of coagulation facto rs was prevented in a dose-dependent manner by adding ascorbate to the plasma before the treatment. Ascorbate was consumed during the treatm ent at an apparently linear rate. Oxidation of urate and coagulation f actors was enhanced when ascorbate had disappeared from plasma, These results indicate that ascorbate is a primary antioxidant against photo oxidation in plasma and that it effectively prevents oxidative damage to coagulation factors and other proteins.