Study of Nonenzymatic Glycation of Transferrin and its Effect on Iron -Binding Antioxidant Capacity

Objective(s) Nonenzymatic glycosylation (glycation) occurs in many macromolecules in aging and diabetes due to exposure of biomolecules to high level of glucose. Glycation can changes function, activities and structure of many biomolecules. Considering this important role of transferrin (Trf) in iron transport and antioxidant activity in plasma this study was carried out to investigate the effect of glycation in these processes. Materials and Methods In this study, human apo-Trf (5 mg/ml in sodium phosphate buffer pH= 7.4) was treated with different concentrations of glucose in different period of times (10 days and 20 days). Rate of glycation was measured using thiobarbituric acid method. The effect of glycation on iron binding antioxidant capacity of apo-Trf was investigated using two methods (RBC hemolysis and fluorescent). Results Result showed that rate of glycation of apo-Trf was increased with increase in glucose concentration and time of incubation (P< 0.05). Lower iron binding antioxidant capacity was observed for glycted Trf as compared to native Trf (P< 0.05). Conclusion Impairment of antioxidant capacity of glycated Trf can suggest a relationship between glycation of Trf and oxidative stress that occurs due to hyperglycemia in diabetic patients.