1. Essential amino acids: It means that the human body (or other vertebrates) can't synthesize them or the speed of synthesis can't meet the needs of the body, so they must be supplied by food protein. These amino acids are called essential amino acids. * * * has eight functions:
① Lysine: it promotes brain development, is a component of liver and gallbladder, can promote fat metabolism, regulate pineal gland, breast, corpus luteum and ovary, and prevent cell degeneration;
② Tryptophan: promoting the production of gastric juice and pancreatic juice;
(3) phenylalanine: involved in eliminating the loss of kidney and bladder function;
④ Methionine (also called methionine); Participate in the composition of hemoglobin, tissue and serum, and promote spleen, pancreas and lymph;
⑤ Threonine: It can transform some amino acids to achieve balance;
⑥ Isoleucine: involved in the regulation and metabolism of thymus, spleen and submandibular gland; The general command of submandibular gland acts on thyroid gland and gonad;
⑦ Leucine: plays the role of balancing isoleucine;
Valine: It acts on corpus luteum, breast and ovary.
Memory Formula of Eight Essential Amino Acids for Human Body
(1) "Borrow one or two egg-colored books"
Homophones: borrow (valine), mono (isoleucine), di (leucine), Ben (phenylalanine), egg (methionine), color (tryptophan), book (threonine) and lai (lysine).
(2) "Fools come to the dormitory to hang their shoes"
Stupid (phenylalanine) eggs (methionine) come (lysine) stay (threonine) stay (tryptophan), air (leucine) and air (isoleucine) shoes (valine).
(3) "Bring one or two books about methyl sulfide"
▲ (valine)-(isoleucine)-bis (leucine) (phenylalanine)-methionine (tryptophan)-threonine (lysine)
Its physical and chemical characteristics are roughly as follows:
1) is a colorless crystal. The melting point is above 230℃, and most of them have no exact melting point, which explains when the released CO2 melts. Soluble in strong acid and alkali solution, except cystine, tyrosine and diiodothyroxine, which are all soluble in water; Except proline and hydroxyproline, it is almost insoluble in ethanol and ether.
2) Alkaline [diaminomonocarboxylic acid, such as lysine]; ; Acidity [monoamine dicarboxylic acid such as glutamic acid]; ; Neutral [monoamine monocarboxylic acid, such as alanine)] three types. Most amino acids are acidic or alkaline to varying degrees, and rarely neutral. So it can combine with acid and alkali to form salt.
3) Because the carbon atoms are asymmetric, they are optically active. At the same time, due to the different spatial layout, there are two configurations: D type and L type. The amino acids that make up protein belong to L-type. In biochemical research, amino acids usually refer to α-amino acids, because all amino acids were hydrolyzed from protein (now they are mostly synthesized) and all amino acids obtained from protein hydrolysis are α-amino acids. As for β, γ, δ and other amino acids ... ω, they are of little use in biochemical research, and are mostly used in organic synthesis, petrochemical industry, medical treatment and so on. There are many kinds of amino acids and their derivatives, most of which are stable in nature and should be stored in a dry place away from light.
2. Non-essential amino acids: refers to amino acids that people (or other vertebrates) can synthesize from simple precursors and do not need to obtain from food. Such as glycine, alanine and other amino acids.
1, 2- naphthoquinone and 4- sodium sulfonate are crimson in alkaline solution (α-amino acid test).
Peptide bond: The carboxyl group of one amino acid is condensed with the amino group of another amino acid to remove the amide bond formed by one molecule of water.
Peptide: A polymer in which two or more amino groups are linked by peptide bonds. Amino acids are compounds linked by peptide bonds, and the products of incomplete hydrolysis of protein are also peptides. Peptides are called dipeptides, tripeptides, tetrapeptides and so on. Depending on the number of amino acids, they are composed of, for example, 2, 3 and 4 amino acids. Generally, oligopeptides are composed of less than 65,438+00 amino acids, and polypeptides are composed of more than 65,438+00 amino acids, all of which are simply called peptides. Amino acids in peptide chains are not free amino acid molecules, because amino groups and carboxyl groups combine to form peptide bonds, so amino acids in peptides and protein molecules are called amino acid residues.
Polypeptides include open-chain peptides and cyclic peptides. In human body, it is mainly open-chain peptide. Open-chain peptides have a free amino terminal and a free carboxyl terminal, which retain free α -amino and α -carboxyl groups respectively, so they are also called N-terminal (amino terminal) and C-terminal (carboxyl terminal) of polypeptide chains. When writing, the N-terminal is usually written on the left side of the molecule, which is represented by (H), so that the amino acid residues in the polypeptide molecule are numbered in turn, while the C-terminal of the peptide chain is written on the right side of the molecule. At present, the amino acid compositions and sequences of about 200,000 kinds of peptides and polypeptides in protein molecules have been determined, many of which are closely related to medicine and have important physiological or pharmacological functions respectively.
Polypeptides are widely distributed in the body and have important physiological functions. Red blood cells are rich in glutathione, which can protect the structure of cell membrane and make the enzyme protein in cells active in reduction. Among various peptides, glutathione has a special structure. Glutamate in the molecule is dehydrated and condensed with α -amino group of cysteine to form peptide bond, and reversible redox reaction can occur in cells, so there are two kinds of glutathione: reduced glutathione and oxidized glutathione.
In recent years, some polypeptide molecules with strong biological activity have been continuously discovered and identified, most of which have important physiological or pharmacological functions. For example, some "brain peptides" are closely related to the body's learning and memory, sleep, appetite and behavior, which increases people's understanding of the importance of peptides, and peptides have become one of the remarkable research fields in biochemistry.
The difference between polypeptide and protein is that, on the one hand, the number of amino acid residues in polypeptide is less than that in protein, generally less than 50, while protein is mostly composed of more than 100 amino acid residues, but there is no strict dividing line between them in terms of number. Apart from molecular weight, it is still believed that peptides generally have no strict and relatively stable spatial structure, that is, their spatial structure is relatively easy to change and plasticity, while protein molecules have relatively strict and stable spatial structure, which is also the reason why protein plays an important role. But in some books, insulin is not called polypeptide strictly because of its small molecular weight. However, both polypeptide and protein are polycondensates of amino acids, and polypeptide is also the product of incomplete hydrolysis of protein.
Patent collection of amino acid preparations
1, amino acid nano selenium and preparation method thereof
2. Polyester containing active drugs and amino acids in the main chain and its preparation method.
3. Compound amino acid capsule and its preparation method
4. A method for preparing D- amino acid by hydrolyzing D-N- carbamoyl amino acid with ion exchange resin.
5. A preparation method of D- amino acid oxidase
6. A method for preparing a series of D-a- amino acids by Burkholderia cepacia JS-02.
Preparation method of 7.3- hydroxy -3- methylbutyric acid (HMB) amino acid salt
8. Cyclic ketones, their preparation and application in amino acid synthesis
9. A human hair amino acid nutritious food or pharmaceutical additive and its preparation method.
10, preparation method of amino acid foliar fertilizer
Preparation method of 1 1 and amino acid-medical stone compound trace element fertilizer
12. Preparation of β -amino acids rich in enantiomers by enzymatic method
13. Preparation of β -amino acids rich in enantiomers by enzymatic method
14, aromatic amino acid derivative, preparation method and medical application thereof
15, l- amino acid acyl -(8- quinolinyl) amine and its derivatives and preparation method thereof
16, stable solid dosage form of amino acid and its preparation method
17, novel amino acid derivatives, their preparation methods and pharmaceutical compositions containing them.
18. Method for preparing amidocarboxylic acid by reacting amino acid with carboxylic anhydride in water.
19, preparation method and application of zinc amino acid
20. A method for preparing optically active amino acids by thermal hydrolysis of N- carbamoyl amino acids.
2. Material basis of life metabolism
The emergence, existence and extinction of life are all related to protein, as Engels said: "protein is the material basis of life, and life is a form of existence in protein." If the human body lacks protein, its physique will be reduced, its development will be delayed, its resistance will be weakened, anemia will be weak, and edema will be formed in severe cases, even life-threatening. Once protein is lost, life will cease to exist, so some people call protein "the carrier of life". Can be said to be the first element of life.
The basic unit of protein is amino acid. If the human body lacks any essential amino acids, it will lead to abnormal physiological function, affect the normal metabolism of antibodies and eventually lead to diseases. Similarly, if the human body lacks some non-essential amino acids, there will also be disorder of antibody metabolism. Arginine and citrulline are very important for the formation of urea. Insufficient intake of cystine will cause insulin decrease and blood sugar increase. For example, the demand for cystine and arginine has greatly increased after trauma. Without it, even if the heat energy is sufficient, protein can't be successfully synthesized. In a word, amino acids can play the following roles in human body through metabolism: ① synthesis of tissue protein; (2) into acid, hormone, antibody, creatine and other ammonia-containing substances; (3) into carbohydrates and fats; ④ Oxidation into carbon dioxide, water and urea to generate energy. Therefore, the existence of amino acids in human body not only provides important raw materials for the synthesis of protein, but also provides a material basis for promoting growth, normal metabolism and maintaining life. If the human body lacks or reduces one of them, the normal life metabolism of the human body will be hindered, and even various diseases or life activities will be terminated. This shows how many amino acids are needed for human life activities.
Second, the position and role in food nutrition
In order to survive, human beings must eat food to maintain the normal physiological, biochemical and immune functions of antibodies, as well as life activities such as growth, development and metabolism. The comprehensive process of food being digested, absorbed and metabolized in the body, promoting antibody growth and development, improving intelligence and physique, resisting aging, preventing diseases and prolonging life is called nutrition. The effective ingredients in food are called nutrients.
Protein, lipids, carbohydrates, inorganic salts (that is, minerals, which contain a large number of elements and trace elements), vitamins, water and dietary fiber, which constitute the most basic substances of the human body and are also nutrients needed by the human body. They have their own unique nutritional functions in the body, but they are closely related in the process of metabolism, participating, promoting and regulating life activities together. The body communicates with the outside world through food, keeping the internal environment relatively constant, and completing the unity and balance of the internal and external environment.
What role do amino acids play in these nutrients?
1. The digestion and absorption of protein in the body is completed by amino acids.
Protein, as the first nutrient element in the body, plays an obvious role in food nutrition, but it can't be directly used in the human body, but can be used by becoming small molecules of amino acids. That is, it is not directly absorbed by the human body in the gastrointestinal tract, but is decomposed into low molecular weight peptides or amino acids by various digestive enzymes in the gastrointestinal tract, and then absorbed in the small intestine and enters the liver along the hepatic portal vein. Some amino acids are decomposed or synthesized into protein in the liver; Another part of amino acids continue to distribute to various tissues and organs with blood, and can freely choose to synthesize various specific tissue proteins. Under normal circumstances, the speed of amino acids entering the blood is almost equal to its output speed, so the content of amino acids in normal people's blood is quite constant. If calculated by 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 in protein, a large number of amino acids were absorbed, and the level of amino acids in blood temporarily increased, and the content returned to normal after 6-7 hours. It shows that amino acid metabolism in the body is in a dynamic balance, with blood amino acids as its balance hub, and liver is an important regulator of blood amino acids. Therefore, food protein is digested and decomposed into amino acids and then absorbed by human body, and antibodies use these amino acids to synthesize their own protein. What the human body needs for protein is actually the need for amino acids.
2. Play the role of nitrogen balance
When the quality and quantity of protein in daily diet are appropriate, the nitrogen intake is equal to the nitrogen discharged from feces, urine and skin, which is called the total balance of nitrogen. In fact, it is the balance of continuous synthesis and decomposition between protein and amino acids. Normal people's daily intake of protein should be kept within a certain range. When the intake suddenly increases or decreases, the body can still regulate the metabolism of protein and maintain the nitrogen balance. Excessive intake of protein, beyond the body's regulatory capacity, will destroy the balance mechanism. If you don't eat protein at all, the tissue proteins in your body will still decompose and negative nitrogen balance will continue to appear. If measures are not taken to correct it in time, the antibody will eventually die.
Step 3 turn into sugar or fat
α -keto acids produced by amino acid catabolism are metabolized along different sugar or fat metabolic pathways. α-keto acids can be synthesized into new amino acids, or converted into sugar or fat, or decomposed into CO2 and H2O through cyclic oxidation of tricarboxylic acid, releasing energy.
4. Produce a carbon unit
Some amino acids produce groups containing one carbon atom during catabolism, including methyl, methylene, alkenylene, methyl, cresol and iminomethyl.
A carbon unit has the following two characteristics: 1. It cannot exist in an organism in a free form;
2. Tetrahydrofolate must be used as a carrier.
Amino acids that can produce one carbon unit are serine, tryptophan, histidine and glycine. In addition, methionine can provide "active methyl" (a carbon unit) through S- adenosylmethionine (SAM), so methionine can also generate a carbon unit.
The main physiological function of a carbon unit is as the raw material for the synthesis of purine and pyrimidine, and it is the link between amino acids and nucleotides.
5. Participate in the formation of enzymes, hormones and some vitamins.
The chemical essence of enzymes is protein (amino acid molecular composition), such as amylase, pepsin, cholinesterase, carbonic anhydrase, transaminase, etc. The nitrogen-containing hormone is protein or its derivatives, such as growth hormone, thyroid stimulating hormone, adrenaline, insulin, intestinal juice stimulating hormone, etc. Some vitamins are converted from amino acids or exist in combination with protein. Enzymes, hormones and vitamins play a very important role in regulating physiological functions and catalyzing metabolism.
6. The demand for essential amino acids in human body
The requirement of essential amino acids for adults is about 20% ~ 37% of that for protein.
Third, the application in medical treatment.
Amino acids are mainly used to prepare compound amino acid infusion in medicine, and also used as therapeutic drugs and synthetic peptides. At present, there are more than 100 kinds of amino acids used as drugs, including 20 kinds of amino acids that constitute protein and more than 100 kinds of amino acids that constitute non-protein.
Compound preparation composed of various amino acids plays a very important role in modern intravenous nutrition infusion and "element diet" therapy. It plays an active role in maintaining the nutrition of critically ill patients and saving their lives, and has become one of the indispensable medical varieties in modern medicine.
Amino acids such as glutamic acid, arginine, aspartic acid, cystine and levodopa can be used alone to treat some diseases, mainly for treating liver diseases, digestive tract diseases, encephalopathy, cardiovascular diseases and respiratory diseases, as well as improving muscle vitality, pediatric nutrition and detoxification. In addition, amino acid derivatives are also promising in cancer treatment.
Amino acids refer to a class of organic compounds containing carboxyl and amino groups under carbon atoms connected to carboxyl groups. It is the basic substance that constitutes protein for animal nutrition.
There are about 22 kinds of amino acids needed by human body, which are divided into non-essential amino acids and essential amino acids (which must be supplied from food).
Essential amino acids mean that the human body can't synthesize them or the speed of synthesis can't meet the needs of the body, so it must be supplied by food protein. These amino acids are called essential amino acids. * * * There are 10 kinds, and their functions are as follows:
(1) Lysine: promotes brain development, is a component of liver and gallbladder, can promote fat metabolism, regulate pineal gland, breast, corpus luteum and ovary, and prevent cell reflux;
(2) Tryptophan: promoting the production of gastric juice and pancreatic juice;
(3) phenylalanine: involved in eliminating the loss of kidney and bladder function;
(4) methionine; Participate in the composition of hemoglobin, tissue and serum, and promote spleen, pancreas and lymph;
(5) Threonine: it can transform some amino acids to achieve balance;
(6) Isoleucine: involved in the regulation and metabolism of thymus, spleen and submandibular gland; The submaxillary gland headquarters acts on (1) thyroid gland (2) gonads;
(7) Leucine: isoleucine with balancing effect;
(VIII) Valine: It acts on corpus luteum, mammary gland and ovary.
Histidine: Regulation of metabolism;
(x) Arginine: It promotes wound healing and is a sperm protein component.