The amino acids required by the human body are divided into non-essential amino acids and essential amino acids. 1, essential amino acids (essentialaminoacid): refers to the human body (or other vertebrates) can not synthesize or synthesis rate is far from adapting to the body’s needs, it is necessary to be supplied by the food protein, these amino acids are called essential amino acids. A total of eight kinds of its role are: ① lysine (Lysine): to promote brain development, is a component of the liver and gallbladder, can promote fat metabolism, regulation of the pineal gland, mammary glands, the corpus luteum and ovaries, to prevent cell degradation; ② tryptophan (Tryptophan): to promote the production of gastric juice and pancreatic juices; ③ phenylalanine (Phenylalanine): involved in the elimination of renal and bladder functions Methionine (also called methionine): participates in the formation of hemoglobin, tissues and serum, and promotes the function of spleen, pancreas and lymph; ⑤ Threonine: has the function of transforming certain amino acids to achieve balance; ⑥ Isoleucine: participates in the regulation and metabolism of the thymus gland, spleen, and subcerebral glands; Subcerebral gland is the commander-in-chief role in the thyroid, gonads; (7) Leucine (Leucine): the role of balancing isoleucine; (8) Valine (Valine): the role of the corpus luteum, mammary glands and ovaries. 2, non-essential amino acids (nonessentialaminoacid): refers to people (or other vertebrates) can be synthesized by their own simple precursors, do not need to obtain from food amino acids. For example, glycine, alanine and other amino acids. 1,2 naphthoquinone, sodium 4 sulfonate deep red in alkaline solution (test for alpha-amino acids) peptidebond: an amide bond formed when the carboxyl group of one amino acid condenses with the amino group of another amino acid, removing one molecule of water. Peptide:A polymer formed when two or more amino acids are covalently linked by a peptide bond. They are compounds in which amino acids are linked by peptide bonds, and the products of incomplete hydrolysis of proteins are also peptides. Peptide according to its composition of the number of amino acids for two, three and four different and were called dipeptide, tripeptide and tetrapeptide, etc., generally containing less than 10 amino acids called oligopeptide (oligopeptide), by more than 10 amino acids called polypeptide (polypeptide), they are referred to as peptide. Amino acids in the peptide chain are no longer free amino acid molecules, because their amino and carboxyl groups in the generation of peptide bonds are combined away, so the amino acids in peptides and protein molecules are called amino acid residues (aminoacidresidue). 1, the material basis of life metabolism The generation, existence and demise of life, none of which is related to protein, as Engels said: “Protein is the material basis of life, life is a form of protein existence.” If there is a lack of protein in the human body, the physical decline, developmental delays, weakened resistance, anemia and weakness, the formation of edema, and even life-threatening. Once the loss of protein, life will no longer exist, so some people call protein as “the carrier of life”. It can be said that it is the first element of life. The basic unit of protein is amino acid. If the human body lacks any one of the essential amino acids, it can lead to abnormal physiological functions, affect the normal conduct of antibody metabolism, and finally lead to disease. Similarly, if the body is deficient in certain non-essential amino acids, antibody metabolism disorders can arise. Arginine and citrulline are important for the formation of urea; insufficient intake of cystine can cause a decrease in insulin and an increase in blood glucose. Another example is that the need for cystine and arginine increases dramatically after trauma, and if they are lacking, they cannot synthesize proteins successfully even if they have enough calories. In short, amino acids in the human body through metabolism can play the following roles: ① synthesis of tissue proteins; ② into acids, hormones, antibodies, creatine and other ammonia-containing substances; ③ into carbohydrates and fats; ④ oxidation into carbon dioxide and water and urea, producing energy. Therefore, the presence of amino acids in the human body not only provides an important raw material for the synthesis of proteins, but also for the promotion of growth, normal metabolism, and maintenance of life provides the material basis. If the human body lacks or reduces one of them, the normal life metabolism of the human body will be impaired, and even lead to the occurrence of various diseases or the termination of life activities. It can be seen how necessary amino acids are in human life activities. Second, the status and role of food nutrition in order to survive human beings need to ingest food to maintain the normal physiology of antibodies, biochemical, immune function, as well as growth and development, metabolism and other life activities, food in the body through digestion, absorption, metabolism, and to promote the growth and development of antibodies, wisdom and fitness, anti-deterioration and prevention of disease, prolonging the life of the integrated process known as nutrition. The active ingredients in food are called nutrients. As the most basic substances constituting the human body’s proteins, lipids, carbohydrates, inorganic salts (i.e., minerals, including macronutrients and trace elements), vitamins, water and dietary fiber, but also nutrients needed by the human body. They have their own unique nutritional function in the body, but in the metabolic process and closely linked, together to participate in, promote and regulate life activities. Organism through food and external contact, to maintain the relative constancy of the inner environment, and complete the unity and balance of the internal and external environment. What is the role of amino acids in these nutrients? 1, protein digestion and absorption in the body is accomplished through amino acids As the first element of nutrition in the body of protein, its role in food nutrition is obvious, but it can not be utilized directly in the body, but through the amino acids into small molecules after being utilized. That is, it is not directly absorbed by the body in the gastrointestinal tract of the human body, but in the gastrointestinal tract after a variety of digestive enzymes, high molecular proteins are broken down into low molecular peptides or amino acids, which are absorbed in the small intestine and enter the liver along the hepatic portal vein. One part of the amino acids undergoes decomposition or synthesis of proteins in the liver; the other part of the amino acids continues to be distributed to various tissues and organs along with the bloodstream, and is left to be selected for the synthesis of a variety of tissue-specific proteins. Under normal circumstances, amino acids enter the bloodstream at a rate almost equal to their rate of output, so the amino acid content of the blood of normal people is fairly constant. For example, in terms of amino nitrogen, the content is 4-6 mg per 100 ml of plasma and 6,5-9,6 mg per 100 ml of blood cells. After a full meal of protein, a large number of amino acids are absorbed, the amino acid level in the blood is temporarily elevated, and after 6-7 hours, the content returns to normal. This indicates that amino acid metabolism in the body is in dynamic equilibrium, with blood amino acids as its equilibrium hub, and the liver is an important regulator of blood amino acids. Therefore, food proteins are digested and decomposed into amino acids, which are absorbed by the body, and the antibodies use these amino acids to synthesize their own proteins. The body’s need for protein is actually the need for amino acids. 2, the role of nitrogen balance When the quality and quantity of protein in the daily diet is appropriate, the amount of nitrogen intake by the feces, urine and skin discharge of nitrogen is equal, called the total nitrogen balance. In fact, it is the balance between protein and amino acid synthesis and decomposition. Normal people should keep the daily intake of protein within a certain range, sudden increase or decrease in intake, the body can still regulate the metabolism of protein to maintain nitrogen balance. If we eat too much protein, beyond the body’s ability to regulate, the balance mechanism will be destroyed. Do not eat protein, the body still decomposition of tissue protein, negative nitrogen balance continues to occur, if not timely measures to correct, will eventually lead to the death of the antibody. 3, transformed into sugar or fat Amino acid catabolism produced by the a-keto acid, with different characteristics, the metabolism of sugar or lipid metabolism pathway. a-keto acid can be synthesized into new amino acids, or transformed into sugar or fat, or into the tricarboxylic cycle oxidation and decomposition of CO2 and H2O, and release of energy. 4, the production of one-carbon units Some amino acid decomposition and metabolism process produces a group containing a carbon atom, including methyl, methylene, methyl alkenyl, methyl fast base, cresol base and methylene and so on. One-carbon units have the following two characteristics: 1, can not exist in free form in the organism; 2, must be tetrahydrofolate as a carrier. Amino acids that produce one-carbon units include serine, tryptophan, histidine, and glycine. In addition, methionine (methionine) can provide the “active methyl group” (one-carbon unit) through S-adenosylmethionine (SAM), so methionine can also produce one-carbon units. The main physiological function of the one-carbon unit is to serve as the raw material for the synthesis of purines and pyrimidines, and is the link between amino acids and nucleotides. 5, involved in the composition of enzymes, hormones, some of the vitamins The chemical nature of enzymes are proteins (amino acid molecules), such as amylase, pepsin, cholinesterase, carbonic anhydrase, aminotransferase and so on. Nitrogen-containing hormones are composed of proteins or their derivatives, e.g., growth hormone, thyroid-stimulating hormone, epinephrine, insulin, and enteric fluid-stimulating hormone. There are vitamins that are transformed from amino acids or exist in combination with proteins. Enzymes, hormones, vitamins in the regulation of physiological functions, catalyze the metabolic process plays a very important role. 6, the human body’s essential amino acid requirements Adult essential amino acid requirements for protein needs about 20% to 37%. Third, in the medical application of amino acids in medicine is mainly used to prepare compound amino acid infusion, but also used as therapeutic drugs and for the synthesis of peptide drugs. At present, there are more than 100 kinds of amino acids used as drugs, including 20 kinds of amino acids constituting proteins and more than 100 kinds of amino acids constituting non-proteins. The compound preparation composed of many kinds of amino acids occupies a very important position in modern intravenous nutritional infusion and “elemental diet” therapy, which plays a positive role in maintaining the nutrition of critically ill patients and saving their lives, and has become one of the indispensable medicinal varieties in modern medical treatment. Amino acids such as glutamic acid, arginine, aspartic acid, cystine, L-dopa and other amino acids work alone to treat a number of diseases, and are mainly used in the treatment of liver diseases, gastrointestinal diseases, cerebral diseases, cardiovascular diseases, respiratory diseases, as well as for improving muscle vitality, pediatric nutrition and detoxification. In addition amino acid derivatives are showing promise in cancer treatment. Amino acids are a class of organic compounds that contain a carboxyl group with an amino group attached to the carbon atom connected to the carboxyl group. They are the basic substances that make up the proteins required for animal nutrition. The human body needs about 22 kinds of amino acids, divided into non-essential amino acids and essential amino acids (must be supplied from food). Essential amino acids refers to the human body can not synthesize or synthesis rate is far from adapting to the needs of the body, must be supplied by food protein, these amino acids are called essential amino acids. There are 10 kinds of them and their roles are as follows: (a) lysine: promote brain development, is a component of liver and gallbladder, can promote fat metabolism, regulate pineal gland, mammary gland, corpus luteum and ovary, and prevent cellular regression; (b) tryptophan: promote gastric and pancreatic juices; (c) phenylalanine: involved in the elimination of renal and bladder function of the depletion of the (d) methionine; involved in the composition of hemoglobin, tissues and blood serum, have (d) Methionine: involved in the formation of hemoglobin, tissues and serum, and has a role in promoting the functions of the spleen, pancreas and lymph; (e) Threonine: has the function of transforming certain amino acids to achieve equilibrium; (f) Isoleucine: participates in the regulation and metabolism of the thymus gland, spleen and hypophyseal glands, which belong to the general headquarters and act on the (1) thyroid gland and (2) gonadotropic glands; (g) Leucine: acts to balance the role of isoleucine; (h) Valine: acts on the luteal glands, the mammary glands and the ovaries. (ix) Histidine: acts in the regulation of metabolism; (x) Arginine: promotes wound healing, sperm protein components.