Novel Encapsulation Of Horseradish Peroxidase And Performance Study

A novel encapsulated enzyme is described by this dissertation. First, the enzyme was chemically modified to get unsaturated double bonds; then the radical polymerization was happened between the modified enzyme and the monomer which also contain unsaturated double bonds; finally, encapsulated enzyme was obtained and the enzyme was multipoint connected to the carrier. Then the preparation process and the catalytic properties in aqueous solution of the encapsulated enzyme were investigated, the influence of the catalytic properties by chemical factors was also studied.The first part of this thesis explores the process of encapsulated horseradish peroxidase(HRP). Amino groups of HRP was modified by the modifier N-acryloxysuccinimide(NAS). The modified HRP was added into a copolymer system, which contained four different kinds of PEG400(200)-di(meth)acrylate ester and acrylamide. The polymerization was initiated by free radicals. Then four novel encapsulated HRP solid particles could be obtained. Experimental results showed that when the mole ratio between HRP and NAS was 1:20000 and modification time was lhour, the modified result was the best. When the materials of the polymerization were 10ml HRP,50mg acrylamide and 5g PEG400(200)-di(meth)acrylate ester.The second part presents the catalytic properties of encapsulated HRP in aqueous. Results show that relative activities of four encapsulated HRP A-HRP(PEG400-diacrylate ester as monomer), B-HRP(PEG400-dimethacrylate ester as monomer), C-HRP(PEG200-diacrylate ester as monomer) and D-HRP(PEG200-dimethacrylate ester as monomer) in aqueous was 107.8%,47.1%, 104.3% and 23.3%; when in 80℃, there were retained a few relative activities of four encapsulated HRP and A-HRP had the highest of relative activity, but there was completely inactivation of free HRP; when C-HRP was reused by five times, the relative activity of C-HRP was retained 62.1% of its initial activities; when HRP were stored by 30 days in 4℃, the the relative activity of A-HRP was almost the same while of the free HRP was dropped 62%, when HRP were stored by 75 days, the relative activity of A-HRP was 55.7% of its initial activities. But the protein was metamorphic when the free HRP was stored by 50 days.It was also studied the influence of the catalytic properties by chemical factors. When in the condition of strong acid (pH=3.0), the relative activity of free HRP was under 8%, while the relative activity of C-HRP was 47.9%; When in the condition of strong alkaline (pH=11.0), the relative activity of free HRP was 13.8%, while the relative activity of C-HRP was 39.7%; When in the condition of pH5.0-7.0, the relative activity of free HRP was steady, but the activity of free HRP was sharply declined when pH value rised, while the activity of C-HRP was remains high. With the valence of metal ion increased, the activity of HRP reduced when in the metal ion solutions. When encapsulated HRP was soaked for 30days in 0.5% SDS at 25, the relative activities of four encapsulated HRP were remains above 36%; when encapsulated HRP was soaked for 30days in urea solution, the relative activity of A-HRP was 62.7%. With logP of solvent increased the catalytic activity of HRP increased.