Research On The Catalytic And Antioxidant Properties Of Heme

Heme is an iron porphyrins, and is a part of hemoglobin cofactor. Previous studies has demonstrated hemoglobin (Hb) has the activity of catalysis for the protection of ischemia-reperfusion injury (I/R) with the generation of tyrosine dimer with hydrogen peroxide. In this experiment we will have a further research for the antioxidant properties of heme and whether it have the same catalytic properties as Hb.In the current research we will establish the tyrosine-hydrogen peroxide-fluorescent system, designed to have a verification of the catalytic properties with heme. For the one hand, after the oxidation of tyrosine there will be generate a new substance with fluorescence properties named tyrosine dimer, so in this system we will detect the interaction of fluorescence of the three substances alone or together with the reaction product, and then the kinetic curves and the measurement of reactants can be get. On the other hand, previous studies has proof that heme and hydrogen peroxide can react with a substance with fluorescent properties, so in this experiment we compared the catalytic properties of heme monomer and the reaction product of heme and hydrogen peroxide for the same concentrations, to verify whether the reaction product will affect the tyrosine dimer fluorescence or not. At the same time, we also carried out the pyrogallol autoxidation, organic radical DPPH (1,1-diphenyl-2 three dinitrophenylhydrazine) clearance and Fenton method to probe whether heme has the anti-oxidants activity in vitro, and set different antioxidants as experimental reference to have an in-depth study of the radical scavenging activity and antioxidant properties of heme. In this experiment we also added a certain amount of tyrosine in various experimental systems, to determine whether tyrosine can enhance the oxidation resistance of heme or not.By way of the above research,we find that heme has catalysis properties andmicromolar concentrations of it has the good ability of antioxidant and free radical scavenging, and tyrosine can enhanced the antioxidant effect of heme. Then we use the ECV-304 human umbilical vein endothelial cell line, and make the glucose oxidase to generate H2O2. MTT, LDH and MDA are used in this experiment to test the injury of endothelial cell, to study the protective and the antioxidant effect of heme on the oxidative damage of vascular endothelial cells in vivo. The results can be drawn that heme has a good protective effect of oxidative damage to cells, and it also has the catalytic ability of tyrosine dimer with hydrogen peroxide. So the heme not only can be used as an excellent catalysts which plays a protective role in the ischemia-reperfusion injury of fight against with the free radical damage, but also can play an vital protective part in the body illness.