Study On Separation Purification Of Low Molecular Weight Corn Peptides And Its Physiological Activity

Reactive oxygen species(ROS),including superoxide radicals(O₂),hydrogen peroxide(H₂O₂) and hydroxyl radicals(OH·) are a group of activated molecules that continuously formed during normal aerobic metabolism.Free radicals are the dissociative molecules,atoms or ions with unpaired electron,having an active chemical property.They are constantly produced and constantly scavenged in organism.Under the physiological condition,the concentration of free radicals,occupying the state of equilibrium,is very lowe Not only do they not damage the organism,but also have some special physiological functions.Under the pathological condition,free radicals generated by physical factor and xenobiotics directly or indirectly cannot be scavenged in time,or the equilibrium of producing and scavenging endogenous free radicals is broken,then the body are injured by free radicals.Testified by generous circumstances,lots of diseases relate to oxygen free radicals and derivants.In the course of cancerous development,free radicals are generated and participated in every stage,otherwise free radicals are also participated in course of cancerous treatment, therefore,it is regarded that the relationship between free radicals and cnacer is very intimate;There is a theory which indicates that oxygen free radical also have some effect to apoptosis,presuming that active oxygen free radicals may be the media or transmitte during the apoptosis.In addition,oxygen free radicals cause other diseases,such as diabetes mellitus,autoimmune disease and so on.Because of the damage by free radicals,it is extremely necessary to scavenge oxygen free radical as well as derivants.So it is important for screening and inverstigating the antioxidants.Recently,more attention has been paid to the bioactive peptide.All kinds of bioactive peptides were prepared from animals,plants and microbes by the means of enzymolytic effect and so on.Compared with traditional drugs,bioactive peptides have some advantage such as no antigenicity,good flavor and absorption easily.The primarily process of corn in our country is mainly on corn starchy,forage,corn protein and o ther primary products,the products have little product and science value.In order to promote corn's append value and extend the corn deep processing industry chain and achieve high added value transformation of corn.The preparation,separation,purification and physiological activity of corn peptide have carried out in following research:1.we use the corn protein----by-product of the corn process to produce bioactive peptide First,we prepared the zein form corn gluten meal using ethanol precipitation.Then the zein is hydrolyzed by a type of alkaline protease,which has a wide substrate specificity,at 50℃and pH 8.0.The degree of hydrolysis was controlled to be 25%.After via a series of separation using molecular sieve,the hydrolysate were freeze-dried and the com peptides(CP) was obtained.2.We examined the CP's positive function of antioxidation effect,This bioactive peptides,the CP from corn protein display a wide-ranging antioxidative properties and capability.As a wide-ranging antioxidant,CP can scavage DPPH radical when 10 mg/ml,the clearance rate is 74.36%,therefore,the CP can be regarded as one kind of extensive antioxidant.3.We examined the CP's positive function to inhibit ACE,when CP concentration is 20mg/l,and CP on the ACE inhibition rate is higher than 40%.With the increase of CP the concentration of ACE inhibition rate is gradually increasing.When CP concentration is 100mg/ml,the ACE inhibition rate of more is more than 80%.From the article,we can see that the CP and its separation and purification products can inhibit the activity of ACE and have a lower blood pressure.4.We also adopted the MTT assay to study the effects of different concentration CP solution on MCF-7 cells proliferation and adhesive capability to Fibronectin.Cellular motility experiment was carried out to assay the inhibitory effect of CP on MCF-7 motility on Fibronectin.On the basis of above content,we not only produced a broad application of the CP,but also confirmed CP can inhibit ACE and had inhibitory effect on the proliferation and adherence of MCF-7 cells to fibronectin, it also could restrain MCF-7 cells from moving on fibronectin.We will provide theoretical foundation and experimental basis for the further development and application of CP.