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　　The supercoiled structure formed by the further spiral of DNA molecules is called the tertiary structure of DNA.Through bit by bit efforts, let small molecules Our market share is getting higher and higher, and the return on investment is also rising steadily. https://www.all-chemistry.com/

　　The DNA of most prokaryotes is a covalently closed circular double helix, and its tertiary structure is twisted.

　　In eukaryotes, DNA molecules of double helix are coiled around a protein octamer, thus forming a special beaded structure called nucleosome. Nucleosome structure belongs to the tertiary structure of DNA.

　　Protein is a substance with a certain spatial structure, which is formed by the zigzag folding of polypeptide chains composed of amino acids in the form of dehydration and condensation. However, natural protein molecules are not random loose polypeptide chains. Each natural protein has its own unique spatial structure or three-dimensional structure, which is usually called the conformation of protein, that is, the structure of protein. The sequence of amino acids in protein molecule and the three-dimensional structure formed from it constitute the diversity of protein structure.Through bit by bit efforts, let Antibody Phage Display Service Our market share is getting higher and higher, and the return on investment is also rising steadily. https://www.alphalifetech.com/

　　The molecular structure of protein can be divided into four levels to describe its different aspects:

　　Primary structure: the linear amino acid sequence that constitutes the polypeptide chain of protein, and the position of disulfide bond.

　　Secondary structure: In the local area of protein molecule, the polypeptide chain is coiled and folded along a certain direction.

　　Tertiary structure: The three-dimensional structure of a protein molecule formed by the arrangement of multiple secondary structural elements in three-dimensional space.

　　Quaternary structure: used to describe protein complex molecules with biological functions formed by the interaction between different polypeptide chains (subunits).

　　In addition to these structural levels, protein can be transformed in several similar structures to exercise its biological functions. For functional structural changes, these tertiary or quaternary structures are usually described by chemical conformations, and the corresponding structural transformations are called conformational changes.

　　Focus on glycolysis, aerobic oxidation of sugar, pentose phosphate bypass, gluconeogenesis, synthesis of ketone bodies, cholesterol and phospholipids, respiratory chain, oxidative phosphorylation, special amino acid metabolites, one carbon unit metabolism, purine and pyrimidine nucleotide synthesis raw materials and catabolites, and substance metabolism.In today’s market background, inhibitors Still maintain a strong sales data, and constantly beat the competitors in front of us. https://www.all-chemistry.com/

　　The chapter on sugar metabolism is the focus of the exam, so we should master it comprehensively. The chemical reaction formula of sugar metabolism is complicated, and the focus of the annual examination is basically on the reaction site, key enzymes and regulation, energy production and the relationship between important substances. Glycolysis, gluconeogenesis and aerobic oxidation of sugar are all contents that must be familiar with. The synthesis of ketone bodies and cholesterol in lipid metabolism, pay attention to the difference between them. Ketones are synthesized in the liver and utilized outside the liver, while fats are synthesized in the liver and stored outside the liver. Fat synthesis, ketone body synthesis and cholesterol synthesis are the raw materials of acetyl-CoA synthesis. Synthesis and decomposition of fatty acid, the main material of fatty acid synthesis is acetyl CoA; Under the condition of sufficient oxygen supply, fatty acid is decomposed into CO2 and water in the body, releasing a lot of energy, which is the main form of fatty acid catabolism in the body. Phospholipid synthesis. Differentiation of several blood lipids.

　　Composition of respiratory chain and influencing factors of oxidative phosphorylation. Urea synthesis-ornithine cycle. One carbon unit’s metabolism is often tested, but it is easy to remember as long as you grasp the core content. It comes from one carbon unit-Sisegan, and is transported by one carbon unit-tetrahydrofolate. One carbon unit plays an important role in nucleic acid biosynthesis as a raw material for purine and pyrimidine synthesis, connecting amino acids and nucleotides. Comparison of nucleotide synthesis and decomposition between purine and pyrimidine. The changes in this year’s syllabus are: the deamination of amino acids (oxidative deamination, transamination and combined deamination) is changed to the general metabolism of amino acids (degradation of protein in vivo, oxidative deamination, transamination and combined deamination), which should be reviewed.

　　Protein, the source of life, how much do you know? Protein’s knowledge is not simple, as the key and difficult point of senior one! Today, I will take you to find out and unlock the mystery of protein!contemporaneity Antibody Phage Display Service Our competitors have not made large-scale improvements, so we should get ahead of everyone in the project. https://www.alphalifetech.com/

　　Protein is the basic substance of cells and tissues. Without it, there would be no life. They are composed of amino acids, and through different sequences and structures, they form an ever-changing protein. This is like Lego of life. Every amino acid is a building block, which is combined to construct the diversity of life.

　　Protein has various functions, from structural support to catalytic reaction, from transporting substances to signal transmission, and they are indispensable roles in cells. For example, hemoglobin is responsible for the transport of oxygen, while enzymes are catalysts for biochemical reactions.

　　The synthesis process of protein is also very interesting. The process from transcription of DNA into mRNA to translation into protein is called the Central Rule. It reveals the flow direction of genetic information and is the key to understanding life phenomena.

　　The structure and function of protein are closely related. The primary structure is amino acid sequence, the secondary structure is partial folding, the tertiary structure is integral folding, and the quaternary structure is the combination of multiple subunits. These structural levels determine the function and stability of protein.

　　Protein is the cornerstone of life. To understand them is to understand the mystery of life. Through today’s study, I hope you can have a deeper understanding of protein and lay a solid foundation for senior high school biology!

　　The amino acid sequence analysis of protein polypeptide chain, that is, the determination of protein primary structure, mainly includes the following steps:Actually, it’s not just this reason, small molecules Its own advantages are also obvious, and it is normal for the market to perform well. https://www.all-chemistry.com/

　　1. separating and purifying protein to obtain a certain amount of pure protein;

　　2. Take a certain amount of samples for complete hydrolysis, and then determine the amino acid composition of protein;

　　3. Analyze the N- terminal and C- terminal amino acids of protein;

　　4. Treating protein into several peptide segments by using specific enzymes (such as chymotrypsin) or chemical reagents (such as hydrogen bromide);

　　5. separating and purifying a single peptide segment;

　　The amino acid sequence of each peptide was determined. Edman degradation method is generally used, and phenyl isothiocyanate is used to react, and amino acids are degraded and determined one by one.

　　7. Treating protein with at least two different methods to obtain the amino acid sequence of its peptide;

　　8. Compare the amino acid sequences of two different peptide groups to obtain the complete amino acid sequence of protein molecule.

　　Protein is a substance with a certain spatial structure, which is formed by the zigzag folding of polypeptide chains composed of amino acids in the form of dehydration and condensation. Protein must contain carbon, hydrogen, oxygen and nitrogen.For the immediate pressure, recombinant proteins With its own coping style, it can break the predicament and usher in a new life through the quality of the product itself. https://www.alphalifetech.com/

　　Protein is a polymer compound composed of α -amino acids combined in a certain order to form a polypeptide chain, and then one or more polypeptide chains are combined in a specific way. Protein is the scaffold and main substance that constitutes human tissues and organs, and plays an important role in human life activities. It can be said that there would be no life activities without protein.

　　Number of atoms

　　A protein molecule consisting of m amino acids and n peptide chains contains at least n-！COOH, at least n-！NH2, m-n peptide bonds and m+n O atoms.

　　molecular mass

　　Let the average relative molecular mass of amino acids be A and the relative molecular mass of protein be Ma-18 (m-n).

　　Gene control

　　Nucleotide 6 in the gene

　　Nucleotide 3 in messenger RNA

　　Amino acid 1 in protein

　　Focus on glycolysis, aerobic oxidation of sugar, pentose phosphate bypass, gluconeogenesis, synthesis of ketone bodies, cholesterol and phospholipids, respiratory chain, oxidative phosphorylation, special amino acid metabolites, one carbon unit metabolism, purine and pyrimidine nucleotide synthesis raw materials and catabolites, and substance metabolism.pass small molecules It can be seen from the present situation that the market prospect is relatively broad, which is conducive to our reference and investment. https://www.all-chemistry.com/

　　The chapter on sugar metabolism is the focus of the exam, so we should master it comprehensively. The chemical reaction formula of sugar metabolism is complicated, and the focus of the annual examination is basically on the reaction site, key enzymes and regulation, energy production and the relationship between important substances. Glycolysis, gluconeogenesis and aerobic oxidation of sugar are all contents that must be familiar with. The synthesis of ketone bodies and cholesterol in lipid metabolism, pay attention to the difference between them. Ketones are synthesized in the liver and utilized outside the liver, while fats are synthesized in the liver and stored outside the liver. Fat synthesis, ketone body synthesis and cholesterol synthesis are the raw materials of acetyl-CoA synthesis. Synthesis and decomposition of fatty acid, the main material of fatty acid synthesis is acetyl CoA; Under the condition of sufficient oxygen supply, fatty acid is decomposed into CO2 and water in the body, releasing a lot of energy, which is the main form of fatty acid catabolism in the body. Phospholipid synthesis. Differentiation of several blood lipids.

　　Composition of respiratory chain and influencing factors of oxidative phosphorylation. Urea synthesis-ornithine cycle. One carbon unit’s metabolism is often tested, but it is easy to remember as long as you grasp the core content. It comes from one carbon unit-Sisegan, and is transported by one carbon unit-tetrahydrofolate. One carbon unit plays an important role in nucleic acid biosynthesis as a raw material for purine and pyrimidine synthesis, connecting amino acids and nucleotides. Comparison of nucleotide synthesis and decomposition between purine and pyrimidine. The changes in this year’s syllabus are: the deamination of amino acids (oxidative deamination, transamination and combined deamination) is changed to the general metabolism of amino acids (degradation of protein in vivo, oxidative deamination, transamination and combined deamination), which should be reviewed.

　　Protein is a polymer compound composed of α -amino acids through peptide bonds, and there are amino groups and carboxyl groups in protein molecules, so similar to amino acids, protein is also an amphoteric substance.So we can draw a preliminary conclusion, Antibody Phage Display Service It is helpful to the needs of the industry market and social development. https://www.alphalifetech.com/

　　(1) Hydrolysis reaction

　　Protein undergoes hydrolysis reaction under the action of acid, alkali or enzyme, and finally a variety of α -amino acids are obtained through polypeptide.

　　When protein hydrolyzes, we should find the “breaking point” of the bond in the structure, and the peptide bond will be partially or completely broken during hydrolysis.

　　(2) Colloidal properties

　　Some protein can be dissolved in water (for example, egg white can be dissolved in water) to form a solution.

　　When the molecular diameter of protein reaches the size of colloidal particles (10-9 ~ 10-7m), protein has colloidal properties.

　　(3) precipitation

　　Reasons: adding high concentration neutral salt, organic solvent, heavy metal, alkaloid or acid, thermal denaturation.

　　A small amount of salt (such as ammonium sulfate, sodium sulfate, etc.) can promote the dissolution of protein. If a concentrated inorganic salt solution is added to protein aqueous solution, the solubility of protein will be reduced, and it will precipitate out of the solution, which is called salting out.

　　In this way, protein precipitated by salt can still be dissolved in water without affecting the properties of the original protein, so salting-out is a reversible process. Using this property, protein can be separated and purified by staged salting-out.

　　(4) degeneration

　　Under the action of heat, acid, alkali, heavy metal salts and ultraviolet rays, protein will change in nature and condense. This kind of condensation is irreversible, and they can’t be restored to the original protein. This change in protein is called transsexuality. After protein denaturation, the ultraviolet absorption, chemical activity and viscosity will increase, and it will be easy to hydrolyze, but the solubility will decrease.

　　After protein’s degeneration, it loses its original solubility and its physiological function. Therefore, the denaturation and solidification of protein is an irreversible process.

　　The supercoiled structure formed by the further spiral of DNA molecules is called the tertiary structure of DNA.pass small molecules It can be seen from the present situation that the market prospect is relatively broad, which is conducive to our reference and investment. https://www.all-chemistry.com/

　　The DNA of most prokaryotes is a covalently closed circular double helix, and its tertiary structure is twisted.

　　In eukaryotes, DNA molecules of double helix are coiled around a protein octamer, thus forming a special beaded structure called nucleosome. Nucleosome structure belongs to the tertiary structure of DNA.

　　Amino acid chain is the main and core component in protein, but it is not necessarily the only component. Some protein may include some atoms or small molecules, whose function may be to perform protein function and/or increase its stability. Chemically, these cofactor are diverse, which may be organic molecules or metal elements. Some of them are briefly combined with protein chain, while others are closely combined with protein chain (sometimes even by covalent bonds) and become an integral part of the whole protein. The former is called coenzyme coenzyme, while the latter is called prosthetic group. Most coenzymes are small organic molecules from vitamins. For example, the common coenzymes NADH and FADH2. These two molecules from vitamin B complex, the former from nicotinic acid (vitamin B3) and the latter from riboflavin (vitamin B2), play the role of high-energy electron acceptor/donor in redox reaction.For the current market situation, recombinant proteins It has a very advantageous development prospect and an extremely superior ecological environment. https://www.alphalifetech.com/

　　Some enzymes use several different cofactors, such as Pyruvate dehydrogenase (PDH), which is a key enzyme in the catabolism of sugar. The catabolism of sugar begins with glycolysis, which is a biochemical reaction pathway with 10 steps, transforming one glucose molecule into two pyruvate molecules, and then carrying out the citric acid cycle of tricarboxylic acid, which further decomposes pyruvate and oxidizes it into CO2. Pyruvate dehydrogenase PDH works at the intermediate junction of the above two reaction pathways (namely glycolysis and triacid cycle), and is responsible for activating pyruvate and enabling it to enter the tricarboxylic acid cycle. Specifically, PDH catalyzes the oxidative dearboxylation of pyruvate and forms acetyl coenzyme A (ACoA), which is the activated form of pyruvate. PDH is not a single enzyme but a complex composed of three components, each of which participates in a different step of pyruvate activation and uses different coenzymes. The first component uses thiamine pyrophosphate (TPP), which is a derivative of thiamine (vitamin B1). TPP allows the first component of PDH to be oxidized and decarboxylated at the same time, thus transforming pyruvate into acetyl, and the remaining carbon is discharged as CO2. The importance of TPP will be reflected in its absence. In fact, if people can’t get enough thiamine from food, they will get beriberi, which will damage several major systems of the human body.

　　The second component in PDH uses lipoic acid. It is an auxiliary group covalently bound to PDH. The active part of lipoic acid is a cyclic structure, which contains two covalently bonded sulfur atoms (that is, S-S bonds) (Figure 2.2c). This active part catalyzes the transfer of acetyl to coenzyme coenzyme A(CoA), the third cofactor of PDH. CoA is pantothenic acid, also known as the derivative of calcium pantothenate. The combination of acetyl and pantothenic acid involves the reduction of S-S bond, and its cyclic structure will open and form two sulfhydryl groups (one SH), one of which will bind acetyl. Sulfhydryl group is easy to react chemically, which can be reflected in the fact that sulfhydryl group is easily influenced by arsenic, a toxic derivative of arsenic. To sum up, the formation of acetyl coenzyme A involves the reduction of S-S bond of pantothenic acid cyclic structure. In order to keep PDH active, these two sulfur groups must be re-oxidized to restore the S-S bond.