Research On The Changing Role Of Proteins Under High Oxygen Storage Of Agaricus Bisporus

In the paper, mushroom was as tested materials. The methods of extracting,SDS-PAGE and two-dimensional electrophoresis, tandem mass spectrometry identification of protein, and etc were studied. At the same time, the physiology and quality of mushroom were analyzed under high oxygen and control treatment.The weight loss rate, whiteness, hardness, cell membrane permeability, PPO and POD enzyme activity, and etc. were determined. The protein expression in different treatment was identified further by two-dimensional electrophoresis and mass spectrometry coupled. Specific research contents include the following aspects:On the basis of single factor experiment, the test parameters by using response surface method were optimized. The optimum technology: extract concentration2.0 mol/L, extract p H8.4, extracting time 8 h, and extraction rate 75.09%. The above parameters are used in SDS-PAGE electrophoresis, by modified Tris-HCl extraction, The changes of protein in the browning during the storage were analyzed by SDS-PAGE. The protein subunits were between 26.4 and 80.8 k D.The TCA/aceton extraction, urea/thiourea extraction, phenol extraction/ammonium acetate precipitation, modified Tris-HCl extraction were compared. Through analyzing of the various methods in the content of protein powder, protein purity and clarity in the band, the results showed the most amount of protein powder was attained by themethod of TCA/acetone and modified Tris-HCI, but with low purity. While the less protein powder with high purity was attained by the method of urea and phenol formulation, meanwhile, the protein bands account was clearer in SDS-PAGE. The phenol formulation has the highest purity, and the best effects. So the phenol formulation was used in two-dimensional electrophoresis.Mushrooms were divided into CK group, 80% O₂ + 20% N2 group and 100%O₂ group, to explore the effect of the high oxygen storage on its physiology and quality. It was found that the high oxygen storage had certain effect on reducing its tissue browning, delaying aging and prolonging the shelf life. And the result of100% O₂ group is slightly better than 80% O₂ + 20% N2 group. In SDS-PAGE figure, these three groups have no differences of protein bands, with no difference between the fresh sample and the browning initial sample, and numbers of proteinbands decreasing obviously in the browning late.Proteins were isolated by two-dimensional electrophoresis in the samples of CK group and 100% O₂ group. 35 different protein points were obtained by tandem mass spectrometry analysis, 34 succeeded and 1 failed from the database. And the differences of proteins were raised in the control group. The identifical proteins were transaldolase, Mevalonate 5-Diphosphate Decarboxylase,S-formylglutathione hydrolase and most unknown proteins. Among them, point6102 coverage was reached 51%. The identified proteins were active enzymes,which was related to energy metabolism and tissue browning process. High oxygen transfer storage effectively maintains the commodity value of agaricus bisporus,delays the aging and prolongs the shelf life based on the theoretical analysis of proteins.