| Collagen peptide is a polypeptide mixture prepared by enzymatic method, acid base method or thermal degradation method. Collagen peptides are widely used in the fields of functional food, skin care, disease control, drug controlled release materials and diagnostic materials. Many studies have shown that collagen peptides have good bioactivity, including antioxidant, inhibition of angiotensin converting enzyme(ACE) activity, improving immunity and preventing osteoporosis. Absorption is the key to the biological activity of collagen peptides. During the degradation of protein, some of the peptides produced in the process can be absorbed directly through the intestine. Collagen was absorbed by different operating vectors. The importance of small peptide nutrition is gradually being recognized. Increasing the absorption rate of collagen peptide in the gut become a hot topic in recent years, it has important significance.After the collagen came into a living body, firstly hydrolyzed into polypeptides by pepsin. In the intestinal tract by trypsin, chymotrypsin and other further degradation, polypeptides become an oligopeptide or amino acids, and then absorb. Trypsin is the major digestive enzymes in the intestine, the restriction sites located after arginine(Arg) and lysine(Lys). The content of Arg and Lys in collagen peptide resulting in the differences in absorption has not been reported. The results showed that amino acids affect the absorption of collagen peptide in mice.In this study, based on ion exchange chromatography with collagen peptide, using high performance liquid chromatography/mass spectrometry and TSQ as analysis method. The study compare the collagen peptide absorption in mice intestine. The result showed that the amino acid composition affecting peptide absorption, providing some guidance for the development of special meals or food for special medical formula. The main findings are as follows:(1)The preparation of CPC and CPACollagen peptides(CPO), with mean MW 1kDa, were treated using cation and anion exchange chromatography respectively, and the eluted peptides were named as CPC and CPA respectively. The result indicated the Arg and Lys content in CPC were 12.2% and 7.4% higher than that in CPO, and the Arg and Lys content CPA were 18.3% and 26.5% less than that in CPO.(2)Animal experimentWith the mice experiment, feed the mice CPO、CPA and CPC. Taking five different time points to collect blood. To determine the dynamic changes of Hyp in serum by amino acid composition. The result of animal test indicated that the Hyp content in mice plasma after intragastric infusion of CPC is 1.39 times higher than that of CPA.The absorption of CPC is better than CPA.(3)Mass spectrometryTo further compare the differences of CPC and CPA polypeptide amino acid sequence, compare the content of Arg and Lys. Nine polypeptides containing Arg and Lys were detected from CPC by LCQ/MS, the content of CPC is higher than CPA. After the cation exchange chromatography, the content of polypeptide containing polypeptides containing Arg and Lys increased significantly. The serum obtained from mice experiment were detected by TSQ, to analyze the content of polypeptide containing Hyp. More Arg/Lys-containing peptides were found in CPC than that in CPA by HPLC-MS analysis. Oligopeptides, Ser-Hyp-Gly, Pro-Hyp-Gly and Leu-Hyp, were found in mice plasma. The plasma concentration of three oligopeptides were 2.1, 1.48 and 1.51 higher after infusion of CPC compared to CPA. This research suggests that the amino acid composition is a key factor affecting peptide adsorption in intestine. |
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