Hydrolysis On Soybean Protein With Directed Hydrolyzing Method And The Study On ACE Inhibitory Peptides

In this study, the amino acid sequences of soybean protein, 7S globulin and 11S globulin can be referred from SWISS-PPROT, GSC et al websites and be complemented in the protein database.Searched the recent literatures about ACE inhibitory (ACEI) peptides home and overseas and renewed the ACEI database.Meanwhile searched and perfected the proteases in the database from ENZYME websites.Otherwise utilized the MS Visual Basic to compile the program about the content calculation of hydrophobic amino acids,hydrolyzation with two proteases, forecast latent peptides and molecular weight calculation of hydrolysates which were added to the"Analytical system for active peptides prepared with directides enzyme hydrolyzing method".According to the program about the content calculation of hydrophobic amino acids,analysed soybean protein, 7S globulin and 11S globulin and screened out the appropriate protein.Then simulated hydrolyzation using the"Analytical system for active peptides prepared with directides enzyme hydrolyzing method",finally according to the amounts of activity peptide from simulated hydrolyzation , used Alcalase and pepsin + pancreatin to hydrolyze soybean protein and 7S globulin.Compared the ACEI activity of hydrolysates by Alcalase and pepsin+pancreantin from the soybean protein isolates and 7S globulin, the results suggested that the ACEI activity of Alcalase hydrolysates was more higher than the activity of hydrolysates by pepsin+pancreantin,and the activity of 7S globulin was as much as the soybean protein isolates.The correlation analysis was done on the weight-average molecular weight distribution between experimental and simulative hydrolysates by Alcalase from 7S globulin,the results showed that the linear relation was significant and the correlation was well.For the sake of enriching the hydrophobic amino acid , used the macroporous adsorbing resin DA201-C and the hydrophobic property of 75% ethanol elution fraction increased 2.26%.Then the enrichment products was on Sephadex G-15 column: sample concentration, 200mg/mL; injectionvolume,1.0mL; flowrate, 0.25mL/min;eluant,0.02mol/L HAC-NaAC buffer solution (pH 4.0) .Further fractionation was performed on RP-HPLC and the highest activity was 96.57% .On LC/MS the amino acid sequences were Phe-Ser(FS),Tyr-Ile (YI) or Tyr-Leu (YL) ,furthermore, the proportion of YL to soybean 7S globulin was 0.009396%.