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.beyond doubt Antibody Discovery It will definitely lead the development direction of the whole industry and let its light bloom in this field. 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.

　　Bed is probably the most consumption life time place! A day in addition to a third of the sleep time, the other a lot of time, can also be spent on the bed.Hope for the future pu-erh tea It can achieve rapid and stable development and serve social development and people’s needs well.

　　Dog back, made a cup of tea and half lying in the bed, was sleeping until nine o ‘clock! Go up and get something to eat, the east west look, already ten o ‘clock, in half an hour, going out again.

　　Back on the playground, the ongoing autumn sports meeting of rehearsal. Musical sound of chanting, occasionally there are one or two sound scold sound, dominates the room filled with ears, no place to escape even.

　　Person, want to quiet for a while now, it’s too difficult. Have a computer, television, mobile phone at home. These things no matter use, is usually open. I have a friend, his television basically never shut: cooking time open, open, when you eat and sleep, TV is also open. Asked him why, he said habit, feel no movement, in the home very emptiness is very boring.

　　Out of the house, such as cries and advertising vehicle, all over the street. Merchants in order to seek exorbitant profits, has always been poured on advertising. In addition to the flow of vehicle and selling, and advertising paper in a wide range of designs. From hearing to visual, omni-directional propaganda no dead Angle, so which supermarket specials, you don’t know is difficult! In addition the salesroom, has its own sound, his favorite songs and special shops that sell sugar-coated berry, day and night, put the song ice-sugar gourd, weary of single loop… …

　　So, now the people want to quiet, to have deep spiritual practice. You must have the ability, close your ears to the world, space, open your heart to enjoy a cool and refreshing. Just such an opportunity, but also not much. Such and such things, always copy your heart very full is a mess. Many want to have a heart quiet ethereal! Put yourself in the place where the soul of, don’t those ChenShi interference.

　　All the fruit in the home, all have no, but how to don’t want to go out to buy. Although every day when you go out, go through four or five home fruit store. Not forget to take money, is to bring the money and forget to buy it. Home is always open the door of that a moment, before crashing. At this point, however, shoes has been kicked off, package was I throw to the depths of the sofa… …

　　And so next time, may is so every time.

　　Used to open the computer, the trouble to listen to the shaoxing opera. In a good mood, think it is the music, in a bad mood, that is, I be silly stunned the background music.

　　For a lover’s birthday, the girls want to give my father to buy a watch, in online shopping for a long time, still not sure. Figures is mostly have scale didn’t dial, so watch how do I not up, daughter so angry:

　　”Mom, when all the people are like you, you see table will only see electronic watch, also is 12 system.”

　　”Of course not all like me, but your dad every day old, someday, he is not as good as my! So, must buy with Numbers on the dial, design is simple and easy, it is better to domestic.”

　　”Domestic mechanical or quartz? What brand do you want?”

　　”To quartz, need not everyday winding, brand to the seagull.”

　　”Gull? Never heard of.”

　　”The Internet, as a Chinese, incredibly don’t know the seagull watch?”

　　A daughter called me again:

　　”Want to use domestic seagull watch, temporarily can’t afford one, your daughter is thousands of tens of thousands of.”

　　Then, my daughter on QQ, send me a link, I open on see, isn’t it? Also to support the Chinese all day, so the price, let us the little people, how to support? A newlywed, bought a watch the seagulls, less than 200 dollars.

　　Love came back from work, said to him. See I wasn’t impressed, he looked at me and said:

　　”You are less than 200 pieces, I was monthly salary less than 120 yuan! For more than a month of wages, or to the present, not thousands of useful!”

　　”Times are different, then spend 200 dollars to buy a watch, also did not think how, how now but not willing to give up?”

　　”Don’t think that way, that was didn’t spend your money.”

　　”You don’t say you bought me a watch, to now you still love dearly!”

　　Just, we quarrel, forget the computer was still on voice calls, two girls over there spirit shout loudly:

　　”How noisy again? Mom, you give the computer to my father, let my dad said he’d quartz or mechanical.” , I put my computer to lover.

　　”I want to mechanical, don’t be too high price, didn’t I give you remit money.”

　　”Dial? Digital or graduated? Color should be black and white or grey days?”

　　”Digital calibration, color should be black and white.”

　　”Oh, is it not a watch? Things are!” I can’t help by chimed in.

　　”Dad, are you sure?”

　　”Sure, your mother rush to surf the Internet!”

　　”Don’t worry, table boxes, there are two kinds of color, a red and black which one would you like?”

　　”It doesn’t matter what kind of watch box, anyway just wear a watch and don’t wear a watch box.” And I say a word of mouth.

　　”Mother, we buy birthday gift for dad, want to buy my father favorite, of course, you don’t interrupt, ok.”

　　”What color do you like table box, what colour will! Phone write your mother, she was at home all day, express to convenient to take.”

　　Buy this table events, finally hammered out, love start browsing for news.

　　”Take headphones to you, I want to quiet for a while.”

　　”Want to quiet, what did you do for dinner?” Yeah, just and daughter discuss watch things, how to forget to do dinner?

　　You see, this want to quiet for a moment, really difficult! You can close the earth is the ear, you don’t shut the appetite of the world! Darling still cooking go to! Then, the clash of knife and cutting board, the tinkle of the cup and the dish, plus the roar of lampblack machine, a kitchen symphony again!

　　”Shut the kitchen door, noisy dead.” Lover to roar, I closed the door of the kitchen. Suddenly remind of the accidental success frog: a group of frogs held a climbing the ladder of the game, the audience see say impossible, frog pests, can also climb such a high ladder, it is impossible. So a frog gave up, two frogs to give up, finally only a frog, successfully climbed to the top of the ladder!

　　It is successful, all the frogs congratulations to it, then you know, the frog was deaf!

　　Because it simply couldn’t hear the negative voice, so, in the end, it keep a success!

　　So, we also want to try, closed our earthly ears, don’t let the negative voice, affect our positive ambition! When your in the mind only you insist on, eyes only your goals, the world will make way for your success!

　　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.precisely because inhibitors The rapid development of, so also brought new opportunities to the industry. 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.

　　The structure of protein molecule determines its properties.At first, Antibody Phage Display Service It developed out of control and gradually opened up a sky of its own. https://www.alphalifetech.com/

　　Being bisexual.

　　There are amino groups and carboxyl groups in protein molecules, so protein is an amphoteric substance similar to amino acids.

　　2. Hydrolysis reaction can occur.

　　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.

　　3. Having the property of colloid.

　　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.

　　The precipitation of protein.

　　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.

　　Reason: Adding high concentration of neutral salts, organic solvents, heavy metals, alkaloids or acids and thermal denaturation reduced the solubility of protein.

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

　　The first is “poverty”In the eyes of peers, pu-erh tea It has good qualities that people covet, and it also has many loyal fans that people envy.

　　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!

　　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.consequently inhibitors I also got a lot of attention and wanted to join the ranks. 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.

　　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.understand recombinant proteins In order to better serve customers and reflect the core competitiveness of products. 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.

　　The first is “poverty”As a representative of the industry, pu-erh tea It is necessary to set a certain example for peers and lead the way in product quality.

　　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!

　　The amino acid sequence analysis of protein polypeptide chain, that is, the determination of protein primary structure, mainly includes the following steps:In the industry, small molecules Has been a leader in the industry, but later came from behind but never arrogant, low-key to adhere to quality. 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.

　　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.If you want to make a big difference in the market, Antibody Phage Display Service It is necessary to intensify the upgrading of products on the original basis in order to meet the consumption needs of consumers. 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.