The Study Of Rice Protein Inhibitory

Because the peptide inhibitor of ACE (Angiotensin-converting enzyme) of the foodsource was high safety and no side effects advantage on prevention and cure in high bloodpressure, getting the peptide inhibitor of ACE has become a hot problem in domestic andinternational scientist. The rice protein is a high-quality protein that a kind of source withmuch essential amino acids for individual growth. Recently, many researches demonstratedthat the rice protein was not only sources of nutrition but also be one of biologically activepeptides. In China, there is no study on the derived-rice protein peptide inhibitor of ACE. Inpresent study, Model of QSAR (Quantitative Structure Activity Relationship) was proposedfor Dipeptide inhibitors of ACE based on MEEV (Molecular electro-negativity edge vector) andthe high inhibitory hydrolysis product were gotten from the rice protein by enzymehydrolyze. By a series of separating way, a new inhibitory peptide was drawn from thehydrolysates.Model of QSAR was proposed for 36 Dipeptide inhibitors of ACE based on MEEV.Throughthe model analysis showed that the hydrophobe amino acid such as aromatic amino acid and sideamino acid on the carbon bottom was important to the ACEinhibitory activity.Comparing the active of the inhibitor of ACE of the hydrolysis product from the riceprotein by the Neutrase with those by the Alcalase, the optimal hydrolysis conditions were:pH 8.0, temperature 55℃,enzyme concentration 20μl/g protein, hydrolysis time 2 hours.Salt was removed by positive ion exchange resin at a flow rate of 10 columnvolume/hour with rate of 97.06%,and by the same way passed the negative in exchange resinthe rate was 95.37%.After the positive and negative the total salt moved rate was 92.57%and the nitrogen recovery rate was 87%.With the conditions 5℃;0.1 Mpa enter pressure, most of the peptide which MW aremore than 6000Da were removed and the peptide which MW are less than 1500Da were93.76% and the IC50 of rice protein hydrolysis product decrease 14.29%after ultrafiltrationwith membranes of MW cut-off 6000Da.The peptide inhibitor of ACE was separated by the gel-chromatography and RR-HPLC(The reverse-phase high performance liquid chromatography) and the product is simplecomponent at such conditions as hydrolusates concentration 100 mg/ml;adding hydrolysates1.5 ml;velocity of flow 0.4 ml/min;pH 4.0;lotion 0.02 mol/L HAc-NaAc.The structure of the peptide was draw by the MALDI-TOF-MS/MS (Matrixassisted-laser desorption/ionization time-of-flight tandem mass spectrometry).The sequenceof the peptide is TQVY (Thr-Gln-Val-Tyr) and IC50 is 18.2 μM.