The Enzyme Modification And Proteomics Research On Soybean11S Globulin’s Solubility And Emulsification

Based on defatted soybean as the raw material to prepare the soybean11S globulin, then the soybean11S globulin was use modified by Alcalase and TGase. Modified condition of soybean11S globulin by transglutaminase(TGase), the emulsification and the solubility of modified protein and molecular mechanism were studied by the SDS-PAGE,2D electrophoresis and MALDI-TOF-MS spectrometer. This paper aims to use proteomic method to investigate the molecular mechanism of the modified soybean11S globulin by TGase, and to provide theoretical and experimental basis for polymerized process of the soybean11S globulin by TGaseThe modification conditions, including the reaction temperature, ionic strength, enzyme amount and pH, were studied. The experimental results showed that the temperature at about45℃, ionic condition I at0.2, pH8.0to9.0, the amount of enzyme to30U/g were good at catalytic reaction. The molecular weight of modified soybean11S globulin subunits concentrated at15KU.The effects of reaction temperature, ionic strength, enzyme amount and pH on modified protein’s solubility and emulsibility were studied and the optimal modified conditions of11S globulin by TGase through response surface method. The optimal reaction conditions were:the reaction temperature at37℃,1=0.08, the amount of enzyme is30U/g, pH8.0. Under the conditions, the solubliry and emulsification reached86.15%,66.00%respectively. By Comparing the solubility and emulsification before and after modification, the results showed that the modified protein s solublity and emulsification had been improved significantly. Before modification the solubility of11S globulin was7.24%, afer reached84.26%. Before modification the emulsification of11S globulin was30.27%, after got64.45%.The molecular mechanism of soybean protein’s crosslinking catalyzed reaction by the TGase was investigated by proteomic method. The main methods include2D electrophoresis and mass spectrometry. the experiment with2D electrophoresis technique studied the changes in the protein before and after modification, and found that there were286different spots in the around of modified protein, of which9spots showed below3.5-fold and1above10-fold in modified protein. The10spots were characterized by MALDI-TOF-MS and the10proteins were identified. The results showed that these proteins were proposed to be involved in seed germination and seed maturation protein.(3-conglycinin α’subunit、 Chain A, crystal structures of recombinant and native soybean (3-conglycinin (3homotrimers、β-conglycinin a-subunit and seed maturation protein PM31. α、β and α’ were main homology or heterology trimers, seed maturation protein PM31was a small Heat Shock Protein, playing an important in role in seed maturing. Chain A, Soybean Trypsin Inhibitor exists in the storage organs of plants, especially seeds. It can hinder from digestion and absorption of nutrients, After enzymolysis-polymerization, Chain A, Soybean Trypsin Inhibitor of soybean11S globulin were reduced, its decrease can improve the nutritional value of soy protein. Alcohol dehydrogenase is a kind of zinc enzymes, play an important role in the food storage, can directly with ethanol as the substrate, catalytic ethanol to acetaldehyde, and then through a series of decomposition, finally can remove too much ethanol produced by the anaerobic respiration, to a certain extent, It can remove damage which ethanol to fruit tissue.