The physiological function of protein

The physiological function of protein The original meaning of protein in ancient Latin is "primary" Although it is a molecule of various substances, it is in the center of various nutrients Modern science has proved that the production and existence of life are closely related to protein Protein is the basis of life Without protein, there is no life Protein is the main substance of human body and the main form of organism At the same time, all kinds of important bioactive substances in human body, such as enzymes, hormones and immune substances, are also mainly composed of proteins In addition, protein is an important component of neurotransmitter, which can regulate the normal osmotic pressure of human body and participate in the composition of various body fluids Specifically, the physiological functions of proteins are as follows: 1 Important components of human tissue All tissues and cells of the human body are composed of proteins, which account for 16%? 19% of the body weight of adults, and their content is second only to that of water These proteins in the body are in a dynamic balance of continuous decomposition, reconstruction and repair About 3% of the proteins participate in the renewal every day Even if the body does not eat human proteins at all, the body still decomposes and synthesizes proteins 2 Substances constituting many important physiological functions in the body For example, hormones regulating various metabolic processes and enzymes that play a catalytic role in metabolism are all composed of proteins as the main raw materials According to different functional characteristics, proteins are also divided into transport proteins that transport various small molecules, ions and electrons; actin that contracts muscles; immunoglobulin that has immune function; collagen that forms the scaffold of the body, etc 3 Maintain body fluid and acid-base balance The water between the normal human plasma and tissue fluid is constantly exchanged to maintain the balance of body fluid In this activity, the protein in human plasma plays an important role When the plasma protein concentration is reduced, the plasma osmotic pressure is also reduced, and the water in the plasma enters the human tissue; otherwise, the water in the tissue enters the human blood Hemoglobin and plasma protein are important components of the buffer system in the blood, which can regulate the acid-base balance of the body The "protein sodium salt / protein" in plasma is a buffering pair, which keeps the blood pH constant in weak alkalinity (pH = 7.35? 7.45) 4 Energy supply In general, energy supply is not the main function of protein But in the process of tissue and cell renewal, after protein is decomposed into amino acids, a small part is no longer used to decompose and produce heat; due to excessive ingestion or not meeting the needs of the synthesis of the chimeric protein, some amino acids are oxidized to produce heat 10% - 15% of the energy needed by human body every day comes from protein In particular, when carbohydrates and fats are inadequate, proteins are used to generate energy The amount of protein stored in the body is very small When the nutrition is sufficient, it is only about 1% of the total body protein This protein, called motilin, is mainly stored in the liver, intestinal mucosa and pancreas, and has no effect on organ function after loss To sum up, the human body must often supplement enough protein to maintain normal physiological activities However, in patients with liver and kidney diseases, it is not good to eat too much human protein, because the liver is an important organ of protein metabolism, the waste generated by protein decomposition is mainly discharged from the body by the kidney, and excessive intake of human protein will increase the burden of liver and kidney.