| Superoxide Dismutase is called SOD for short. It is a sort of acidic metal enzyme and isextensively existed in the body of animal, plants and micro-organism. SOD is existed in any aerobiccell. According to the metalion contained, SOD is devided into four types: Cu/Zn-SOD, Mn-SOD,Fe-SOD and Ni-SOD. Among the total, SOD is studyed more.SOD can catalyze·O2- to take place dismutation reaction. As a result, it has the functions ofdeferring senility, elevating immunity of organism and enhancing resistance to illness. There aremany defects as high cost, containing pyrexin and etc. It was not only widely used in medicine,health maintenance, but also used as additives in functional food.At present, scientists have already done a lot of research on mechanism, purification andapplication of SOD in the world, but have paid more attention to the aspect of obtaining SOD fromthe material of animal blood. Besides the safe reason, in this thesis, corn embryo used as material ismainly because of the plentiful material source and low price.JiLin province is one of the most important home of corn in China. The yield and stocks ofcorn comes out top in the world every year. But because of lacking extensive utilization, hightechnology, high additional value and potentiality, the advantage of JiLin corn industry can notexert sufficiently by far. By this project, corn industry chain can be extended. The extensiveutilization in high additional value of corn can be put into practice, and the economic benefit of cornprocess business can be promoted significantly. It is one of the efficient paths to resolve the cornproblems in JiLin province fundamentally.Corn embryo is 10～13％in corn kernel. SOD is mainly contained in corn embryo. Cornembryo SOD to albumn SOD is 1.9. It is illustrated that the content of corn embryo is more thanalbumn. Therefore, the work load is lessen for the extraction from corn embryo and the multiple useis more reasonable.In this thesis, corn embryo used as material, SOD is extracted by supercritical CO2 fluidextraction, low temperature pulverization and supersonic. The enzyme is pretreated by thermal denaturation and acetone precipitation. SOD is separated and purified by column chromatographywith SephadexG-75. It is scanned absorption band by spectrophotometer.This thesis is source of science tackle key project《Study on the abstraction technology andapplication of corn radical scavenger》of ChangChun science technology department. It has beendone much research on extraction and purification of SOD and obtained results as below:1. The fat and foreign flavour is taken off from the raw material by supercritical CO2 fluidextraction. It is easy to the extraction of SOD in the later work. Defining the optimum conditions ofsupercritical CO2 fuid extraction: the extraction pressure is 20 MPa, the extraction temperature is40℃, the extraction time is 100min and the flow is 15L/h;2. The cell is broken into pieces at premise of maintaining enzyme activity by the application ofsupersonic. Defining the optimum conditions of supersonic: liquid to solid is 1 to 25, the time is 6s,the times is 40 and the time cell is 2s;3. Thermal denaturation and acetone sediment is combined for extraction. Thermal denaturationis convenient and the effect is notable. The purpose of acetone addition is as below: one is removinghybridprotein, the other is to condense enzyme. Deploying the extraction method of thermaldenaturation and acetone precipitation: the thermal denaturation time is 15min, the temperature is60℃, the enzyme activity yield is 88.30％, the removal yield to protein is 77.12％, the specificactivity is 188.39U/mg, the purify multiple is 3.86; The acetone addition is 1.5 times, the enzymeactivity yield is 52.24％, the removal yield to protein is 96.33％, the specific activity is 694.96U/mgand the purify multiple is 14.24;4. SephadexG-75 column chromatography purification has many good qualities, such asefficient, simple equipment ,conveniently manipulate and gentle conditions. After purification, theenzyme activity yield is 40.56％, the removal yield to protein is 99.36％, the specific activity is3079.41U/mg, the purify multiple is 63.09;5. SOD is carried out qualitative analysis by ultraviolet spectrophotometry. According to thecomparison between standard preparation and sample, we can determine the material extracted isSOD. By ultraviolet spectrophotometer, the scanning result is that the peak of ultraviolet absorptionof SOD from corn embryo is at 260nm. It is the same to standard preparation. It is illustrated thatthe category of corn embryo is Cu/Zn-SOD. |
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