Hemoglobin As Mimetic Enzyme And Immobilized Enzyme

Enzymatic reaction and mimetic enzyme are the most important issues in the pop field such as supramolecular chemistry and biomimetic chemistry. Hemoglobin (Hb), which was adopted as the biomimetic enzyme of horseradish peroxidase (HRP) for their similar structure in activity site, was used here to study in details its catalytic behavior both in the aqueous media and AOT reversed micro-emulsions. The mechanism on the peroxidase activity of Hb was expounded in the molecular level. The catalytic behavior of Hb and HRP were compared in two media above. Structure and properties of the polymer obtained in reversed micro-emulsion by Hb was measured. Hb was firstly adopted to be immobilized on cross-linked polyacrylamide and chitosan, in order to study its peroxidase activity on carriers. The main conclusions were showed as follow:1. Compared with HRP, hemoglobin showed its peroxidase activity in the reaction of phenol/4-AAP/H2O2. Different from HRP, hemoglobin got its higher activity in the solution with pH value between 9.0 and 10.5, while HRP has a higher activity in neutral media (pH6.5-7.5).2. Hb in alkaline media encapsulated AOT reversed micro-emulsions showed a typical peroxidase activity like HRP, which was siglhtly different from hemoglobin in aqueous media. It might be explained that the comformation conversion of hemoglobin from aqueous media to AOT reversed micro-emulsions endued hemoglobin with an enhanced peroxidase activity.3. Hemoglobin immobilized on both cross-linked polyacrylamide and chitosan showed its peroxidase activity, yet the activity receded greatly. Hemoglobin immobilized on chitosan could have a higher laden quantity and reclaimed activity.4. The structure and properties of the polymer of o-phenylendiamine obtained in AOT reversed micro-emulsions was measured by means of 'HNMR, FTIR, UV-Vis, WAXD, GPC, APM and so on. The result showed that the obtained product was an aromatic heterocyclic polymer constructed in a linear and trapeziform alternatively.5. Thermal analysis and electroanalysis acquired some useful data. Thermal analysis showed that the obtained polymer has a outstanding thermal endurancewith only 30% loss in 700 , AFM got the charge distribution of the polymer.6. AFM was used to study the reaction process of o-phenylendiamine catalyzed by Hb in AOT reversed micro-emulsions. The result showed that the obtained polymer particals were well-proportioned nano-microspheres.