Investigation On The Bioactivity And Conformation Of Rapeseed Peptide

After digestive enzymes hydrolyzed, protein is absorbed in the form of oligopeptide. Some oligopeptides not only provide nutrients which human growth and development needed, but also prevent and control disease, regulate physiological functions. Rapeseed peptide (RSP) is rich in amino acid, the amino acid composition of which is well-balanced. Besides,it contains a variety of bioactivities. Deep processing and utilization of RSP has become a new hot research in plant peptide field.In this study, the physicochemical properties, separation and purification, bioactivity and conformation of RSP were systematically studied, using the latest modern technology including column chromatography system, liquid chromatography-mass spectrometry (LC-MS), FT - Raman spectroscopy, infrared spectroscopy and molecular simulation. The main results are shown as follows: A research on rapeseed protein was sequentially hydrolyzed with alcalase and flavourzyme were performed. Based on this, the physicochemical properties of RSP were studied. RSP was separated by Sephadex chromatography into four components: RSP-1,RSP-2 , RSP-3 and RSP-4.The bioactivities of crude rapeseed peptide and its fractions were investigated, including the free radical scavenging and ACE inhibition. In all fractions, the RSP-4's ABTS free radical scavenging capacity (TEAC value = 0.24) and ACE inhibition capacity (IC50 = 0.19 mg/mL) were strongest, whereas the DPPH free radical scavenging activity of RSP-4 (IC50 = 0.18 mg/mL) was slightly lower than that of RSP-1 (IC50 = 0.125 mg/mL) and RSP-2 (IC50 = 0.125 mg/ mL).The conformation of RSP-4 was first investigated by modern technique including LC-MS, FT - Raman spectroscopy, infrared spectroscopy and molecular simulation. LC-MS determined the molecular weight of RSP-4 was 977Da, combining with database search deduced its amino acid sequence was PFDSYFVC. FT - Raman spectroscopy and infrared spectroscopy verified the amino acid composition information obtained from LC-MS. FT - Raman spectra showed that the secondary structure of RSP-4 wasβangle. Molecular simulation predicted the three-dimensional structure of RSP-4. Peptide was synthesized in accordance with the RSP-4 sequence and determined its bioactivity.This study in-depth investigated the bioactivity and conformation of RSP. These results not only provide a scientific and theoretical basis for natural peptide in biomedical application, but also give new ideas to the source of development and application of plant peptide.