Encyclopedia of life

Amino Acid Sequence Analysis

　　The amino acid sequence analysis of protein polypeptide chain, that is, the determination of protein primary structure, mainly includes the following steps:For the immediate pressure, inhibitors 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.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.

There are amino groups and carboxyl groups in protein molecules

　　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.In order to facilitate users to have a better experience, recombinant proteins Many attempts have been made to upgrade the products, and the results are also very good, and the market performance tends to be in a good state. 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.

There are three things that one can not wait for in one’s li

　　The first is “poverty”contemporaneity pu-erh tea Our competitors have not made large-scale improvements, so we should get ahead of everyone in the project.

　　Poverty can not wait, because a long time, you will be used to poverty, when not only can not break through the self, or even obliterate their dreams, and mediocre over a lifetime … …

　　The second is “dream”

　　Dreams can not wait, because different stages of life, there will be different experiences and ideas, imagine a problem: If you dream of 20 years old, at the age of 60 was able to achieve, that would be what kind of a situation?

　　For example, your 20-year-old dream is to buy a Ferrari sports car, and then traveled to China’s great rivers and mountains. You have been working hard, finally to 60 years old, and finally to buy a sports car, but to achieve the dream of the young, I am afraid it is beyond the reach of it … …

　　The third is “family”

　　Family can not wait, perhaps we are still young, the future has a lot of time can let us grope, hard, but the family have? They still have time for us to succeed? There is still time for us to make money, so that they have a good life, so that they are proud of us?

　　Trees for static and wind, the child wants to support and pro-not wait. This is a lot of people’s pain, but also a lot of people a lifetime of regret!

Amino Acid Sequence Analysis

　　The amino acid sequence analysis of protein polypeptide chain, that is, the determination of protein primary structure, mainly includes the following steps:In order to achieve the goal, inhibitors Turn cocoon into butterfly, constantly polish product quality, improve business ability, and finally have a place in the market. 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.

Amino acid chain is the main and core component of protein.

　　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.Therefore, recombinant proteins Only then will more and more pump owners cheer for it and spread the value and function of the brand. 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.

There are three things that one can not wait for in one’s li

　　The first is “poverty”In order to facilitate users to have a better experience, pu-erh tea Many attempts have been made to upgrade the products, and the results are also very good, and the market performance tends to be in a good state.

　　Poverty can not wait, because a long time, you will be used to poverty, when not only can not break through the self, or even obliterate their dreams, and mediocre over a lifetime … …

　　The second is “dream”

　　The third is “family”

　　Trees for static and wind, the child wants to support and pro-not wait. This is a lot of people’s pain, but also a lot of people a lifetime of regret!

Organic chemistry the molecular cornerstone of life

　　Organic chemistry is an important branch of studying carbon compounds, involving the source, structure, properties and other aspects of organic matter, and providing revelation for the material basis of life phenomena. It plays a key role in medicine, industrial production and other fields, but it still faces challenges such as green synthesis and drug molecular selectivity. Organic chemists are constantly exploring new reaction mechanisms and synthetic methods to promote the development of the discipline.We have every reason to believe. Chemical Custom synthesis It will become the mainstream of the industry and will gradually affect more and more people. https://www.all-chemistry.com/

　　Generated by the author through intelligent technology

　　In the vast universe of science, organic chemistry is like a bright star, leading us to explore the mystery of life. As a subject of studying carbon compounds, organic chemistry, with its unique charm, closely links all fields of natural science and reveals the material basis of life phenomena for us. Organic chemistry, an important branch of chemistry, is a subject that studies the source, structure, properties, separation, preparation, application and related theories of organic matter. “Organic matter” here refers to compounds containing carbon elements, such as alcohols, aldehydes, carboxylic acids, etc. It is worth noting that although organic matter mainly comes from organisms, with the development of science and technology, people have been able to synthesize many artificial organic compounds with biological activity, such as drugs, dyes, plastics and so on.

　　The main research contents of organic chemistry include: synthetic chemistry of organic matter; Metal organic chemistry and elemental organic chemistry; Physical and theoretical organic chemistry; Stereochemistry; Bioorganic chemistry; Natural product chemistry; Chemistry of organic materials.

　　The importance of organic chemistry:

　　1. Basis of life: From the origin of life to the growth and development of organisms, carbon always plays a vital role. Through the study of organic chemistry, we know the structure and function of biological macromolecules such as protein, nucleic acid, sugar and lipid, which are the material basis of life.

　　2. Key in the field of medicine: Many drugs and bioactive substances are organic compounds, such as antibiotics, antiviral drugs and hormones. By studying the structure and function of these substances, scientists are constantly discovering new treatments to protect human health.

　　3. The core of industrial production: Organic chemistry plays an important role in industrial production. For example, in the process of petroleum refining, heavy hydrocarbons in petroleum can be converted into light hydrocarbons by the action of catalysts; In the process of plastic synthesis, organic chemical reactions provide a steady stream of power for the plastic industry. Although organic chemistry has made remarkable achievements in many fields, it still faces many challenges.

　　First of all, in environmental protection, how to realize green synthesis and reduce the discharge of harmful waste is an urgent problem for organic chemists.

　　Secondly, in the field of medicine, how to improve the selectivity of drug molecules and reduce side effects is also a difficult problem to be solved urgently. Faced with these challenges, organic chemists are constantly exploring new reaction mechanisms, catalysts and synthetic methods. I believe that in the near future, organic chemistry will bring us more surprises and inject new vitality into the development of human society. Organic chemistry, as a discipline to study the molecular cornerstone of life, plays an important role in natural science. Let’s walk into this wonderful world hand in hand, grow in exploration, break through in innovation, and jointly write a bright future of organic chemistry.

Levels in protein’s Structure

　　Most protein is like a jumble of atoms packed together. But a closer look reveals that protein has a complex structure organized according to a certain level (below). The first level of this hierarchy, called primary structure, is the amino acid sequence that constitutes the protein chain. Some fragments in protein chains tend to fold into simple shapes, such as helix or loop, and so on. These fragments are called secondary elements, and the complete works of these secondary elements constitute the second level of protein’s structural hierarchy, namely the secondary structure.In order to facilitate users to have a better experience, recombinant proteins Many attempts have been made to upgrade the products, and the results are also very good, and the market performance tends to be in a good state. https://www.alphalifetech.com/

　　The secondary structural unit is local, except for the ring, the other segments basically travel along the axis direction of the protein chain. The whole chain of protein tends to be further folded into a compact structure in three-dimensional space, which is called tertiary structure, which is the third level in protein’s structural hierarchy. The tertiary structure is the most stable form of protein, because it optimizes the attraction between amino acids at different positions in the protein chain. Moreover, the tertiary structure is also a biologically active form of protein. If this form is destroyed, protein will lose some or all of its functions. Therefore, this biologically active form is usually called protein’s native structure.

　　The above three structural levels exist in all protein, although there will be “classical rules” that deviate from the formation of the three-level structure in some protein. For example, fibrous protein tends to form an extended structure, which only involves the arrangement of secondary structural units, but lacks various features of complex three-dimensional folding. Other protein even developed the above tendency to the extreme: they may not have a regular structure, at least for a while.

Your life needs to understand

　　The reason why people live tired, is not fit the shelf, tear can not open face, untied plot (the reason is very simple)At first, pu-erh tea It developed out of control and gradually opened up a sky of its own.

　　Your life needs to understand the stand in their own position, not everyone is in line with your appetite; standing in other positions, you can also to all the appetite? (Tolerance of others)

　　People who can simplify complex problems are talented people, and it is silly to complicate simple problems. (People are often willing to be a fool)

　　A woman most admired men talented, most hated men are too stingy, most afraid of men do not live up to expectations. (Men afraid of the old woman angry)

　　Itching sometimes worse than pain, hate is often easier than love (paradox of life)

　　The opportunity for everyone is equal, you can not shoot the chance, but the opportunity comes when you can not do without bullets (doing business is to do this)

　　Love is like a smallpox, and each of us has to go through it once, and, as with smallpox, we will only get once in a lifetime. You never have to worry about getting a second time.

　　Ancient love stories and more contemporary love accident (different times).

　　A person who does not make mistakes usually can not accomplish anything, and there are no shortcomings, often with little merit (Lincoln’s experience).

　　Businessmen are “people who can talk,” businessmen are “people who can give birth to ideas.” (Alternative explanation)

　　There are seven virtues: First, do not get the ax, the second is not to interrupt other words, the third is not anxious for success, four questions should be targeted, five answers to meet the reasonable, six is to have a beginning and end, seven is to Based on reality. (Ancient Jewish Proverbs).

　　Unit to work overtime every day; home never stick; mobile phone home to close; SMS reading on the delete; go to bed snoring shaking; underwear often wear back. (With an affair of the six symptoms).

　　Do what you think can not do (how much heart, how far the road).

　　The heart is a two-bedroom house, one is suffering, one is happy. People can not laugh too loud, or laughter will wake up next to the pain. (To avoid very happy).

　　If you marry a wise and virtuous wife, you will be happy; if you marry a frivolous bitch, you will become a philosopher. (Marriage useful).

　　Can not tell, can not cry, is the most bitter (life reflected).

　　Where to fall, just lie down (some pessimists).

　　The real question is not whether the spouse is the best person, but whether you are trying to be the best person for your spouse (the Happy Marriage Bible).

　　The only advantage of telling the truth is that you do not have to remember what you said (Quotations User).

　　You can offend busy people, because they do not have time to care about you; you must not offend idlers, because they have time to deal with you. (Do not offend idlers).

　　If you can not change your face, then you change your face (not beautiful, it can be very cute).

　　Than bathing, washing the sauna is more important is the brainwashing, bath does not wash will be distributed odor, brain wash will be eliminated by the times (we often forget this).

　　Do not believe your memories, the person inside, not necessarily the same miss you (with memories of the road, rather than holding the memories of life).

　　There should be a better way to start a new day than waking up every morning (office worker philosopher).

　　Toad want to eat swan, good kind, small things with ambition (to educate the next generation).

　　Rich does not have much, but less luxury. (New view of wealth).

Structure and function of biological macromolecules

　　Classification of amino acids, several special amino acids, molecular structure and physical and chemical properties of protein, composition of nucleic acid, double helix structure of DNA, basic concept of enzyme, Michaelis equation, coenzyme composition.in fact inhibitors It is more and more welcomed by our customers, and its market performance is gradually improving. https://www.all-chemistry.com/

　　Memorize 20 kinds of amino acids and try to remember English abbreviations and codes as much as possible, because exams often appear directly with codes. Protein’s molecular structure often examines the manifestations of various levels of structure and their bonds. The physical and chemical properties of protein and the purification of protein usually use the physical and chemical properties of protein to purify protein without destroying the structure of protein. Pay attention to the identification of amino acids and physical and chemical properties of protein. The basic unit of nucleic acid is nucleotide, which is composed of multiple nucleotides, and the connecting bond between nucleotides is 3′, 5′- phosphodiester bond. DNA double helix structure, in which two bases exist in strict accordance with A = T (two hydrogen bonds) and G triple C (three hydrogen bonds), and the characteristics of various RNA.

　　In addition, we should pay attention to some commonly used concepts in nucleic acid problem solving. The first thing that enzymes should pay attention to is some basic concepts, such as ribozyme, deoxyribozyme, enzyme activity center, isozyme, isomerase and so on. The key point of the Metric Equation test is V=Vmax[S” target=_blank>/Km+[S” target=_blank>, which explains the equation of the relationship between the concentration of enzymatic reaction and the reaction speed. In the exam, candidates are sometimes asked to do simple calculations according to this equation before they can answer. The difference of several inhibitors.

　　According to the characteristics of allosteric enzymes, it should be noted that allosteric regulation can cause conformational changes of enzymes. It is important to pay special attention here that configuration refers to the basic structural composition of substances, and conformation refers to the spatial change of substances. Allosteric regulation can cause the conformational change of enzymes, but not the conformational change of enzymes.