Absorption and metabolism of soybean polypeptide

2015-01-23 classification: function 0 people comment on the abbreviation of soybean polypeptide, namely "peptide based soybean protein hydrolysate", which is the protein hydrolysate obtained by the special treatment of soybean protein after the action of protease The essential amino acid composition of soybean polypeptide is exactly the same as that of soybean protein, but the content is more abundant and balanced, and the polypeptide compound is easy to be digested and absorbed by human body, which has the functions of disease prevention, treatment and regulation of human physiological function Soybean polypeptide is a potential functional food base material, which has gradually become a healthy food in the 21st century According to the traditional model of protein metabolism, the protein ingested as food is usually considered to be digested into small peptide by pepsin in the stomach, then hydrolyzed into free amino acids by trypsin and chymotrypsin in the small intestine, so as to be absorbed and utilized by human body or animals Therefore, the need of human or animal for protein is the need for essential amino acids and synthesis of non essential amino acids However, in modern experiments, when using test tube to simulate in vivo conditions for enzyme decomposition, the amino acids can not be completely decomposed Most of them stay in polypeptide state In addition, the reverse small intestine experiment and small intestine perfusion experiment with the removed mouse small intestine have proved that soybean polypeptide can pass through the small intestine mucosa and be directly absorbed by the intestine without degradation At present, there are two main views about the absorption mechanism of peptides: (1) there are two independent transport mechanisms of free amino acids and small peptides in the absorption of nitrogen-containing substances The study of brush border membrane capsule (BBMV) shows that the absorption of peptide has electricity production, it is a synergistic transport related to H +, and in the process of absorption, it needs an inward H + gradient The absorption of amino acids is carried out by different Na + pump or non Na pump transport systems Compared with amino acids, the absorption system of peptides has the characteristics of fast absorption, low energy consumption, and not easy to saturate, and there is no competition and inhibition in the transport of various peptides ② Due to the influence of high osmotic pressure, amino acids move from the surrounding tissue cells to the stomach, which slows down the movement of water from the stomach to the small intestine The protein needs to be digested in the small intestine, so the absorption speed is also slowed down For soybean polypeptide, these conditions do not exist, because its osmotic pressure is lower than that of amino acid, and its movement rate from stomach to small intestine and absorption rate in small intestine are faster This non selective absorption is of great significance for the expression of peptide bioactivity in host In addition, the absorption of peptide with larger molecular size is caused by the empty site or endocytosis left by the cell abscission in the epithelial cell layer In a word, the way of peptide absorption is that the absorbed peptide not only acts as the provider of amino acids, but also may transmit the information of peptide structure (including amino acid composition and sequence) to the host, showing completely different biological activity from free amino acids.