Yearly Archives: 2024

　　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.contemporaneity small molecules Our competitors have not made large-scale improvements, so we should get ahead of everyone in the project. 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 reason why people live tired, is not fit the shelf, tear can not open face, untied plot (the reason is very simple)To get brand praise, pu-erh tea It is necessary to have the spirit of constantly improving the quality of products, but also to have a bunch of eternal heart fire.

　　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).

　　Separation and purification of protein;By comparison, it can be seen that small molecules It has certain advantages and great cost performance. https://www.all-chemistry.com/

　　1. Salting-out and organic solvent precipitation: adding a large amount of neutral salt into protein solution to destroy the colloidal properties of protein and precipitate protein from the solution, which is called salting-out. Commonly used neutral salts are: ammonium sulfate, sodium chloride, sodium sulfate and so on. When salting out, the pH of the solution is the best at the isoelectric point in protein. Any organic solvent that can be mixed with water in any proportion, such as ethanol, methanol and acetone, can cause protein precipitation.

　　2. Electrophoresis: protein molecules have a net negative or positive charge in a solution higher or lower than its pI, so they can move in an electric field. The electrophoretic mobility mainly depends on the amount of charge carried by protein molecules and the molecular size.

　　3. Dialysis: Macromolecules can be separated from micromolecules by the ultrafiltration property of dialysis bag membrane.

　　4. Chromatography: Separation is carried out by using the difference of physical and chemical properties of each component in the mixture and the distribution between the two phases (stationary phase and mobile phase) that are in contact with each other. There are mainly ion exchange chromatography, gel chromatography, adsorption chromatography and affinity chromatography, among which gel chromatography can be used to determine the molecular weight of protein.

　　5. Ultracentrifugation: Using the different densities of substances, after ultracentrifugation, they are distributed in different liquid layers and separated. Ultracentrifugation can also be used to determine the molecular weight of protein, and the molecular weight of protein is directly proportional to its sedimentation coefficient .

　　Protein is the “building material” of organisms and cells, such as protein in muscles, and human hair and nails are all made of protein.In view of the actual needs of society, Antibody Discovery We need to change some original problems to better serve the society and benefit people. https://www.alphalifetech.com/

　　Catalytic function:

　　The chemical essence of most enzymes in organisms is protein. In our daily life, we also use enzyme-added washing powder, which can effectively remove stains.

　　Immune function:

　　In our present environment, there are bacteria and viruses everywhere, and our body will not get sick every three days with an immune system, and immune proteins, such as antibodies, play a key role in this.

　　Transport function:

　　Protein with transport function can be divided into two categories, one is familiar to us-hemoglobin in red blood cells, which is used to transport oxygen; The other is the carrier protein on biofilm, which is used to transport amino acids, glucose and other substances.

　　Adjustment function:

　　Some protein can transmit information and regulate the life activities of the body. Such as insulin, which regulates glucose metabolism.

　　Life is a fleeting moment in the river of time, mankind do everything possible to seek forever and everlasting, but did not think, in fact, as long as the pace of their own slow down mentality flat, live in the present, then life will naturally become long and distant .At first, pu-erh tea It developed out of control and gradually opened up a sky of its own.

　　When I did not write a magazine before, I did not know that the time had come in advance. A draft of March or even April has been prepared in January. In the draft of the forum while watching the side gripped, his year has not yet ended, did not make a point, there people work has been a year, almost equal to the end. Years here, was actually can not wait to catch up with the speed of flight, how to make people panic?

　　The length of time is defined by man himself. 365 days a year, divided into four seasons, twelve months. Here, people always catch up with me like the game, to see who can one day into a day. Our ancestors know, if the decade into a year, we will so impatient it?

　　Days not used, can only be used to recover. Self has no intention to enter this door, it fell into such a turbulent swirl. Calendars and clocks on the numbers can only represent the past, because today to do, is already the future. Obviously is the spring, but the men have been doing non-stop fall thing.

　　There is nothing worthy of gratification, no reason for youth just a short length of a bit like others. What is the use of walking in front, time falls behind, urging the old soul and face it in vain.

　　The fast pace of modern people, nothing more than to speed up the clock of life, their own pressure and persecution of a way, only to more fully squeeze the juice of life to obtain value and fame. But I see it is faster and more leave no room for the consumption and flight. How, a ton of gold can be exchanged for even a second time?

　　Americans always run in front of the world, even spend today are tomorrow, the result? The financial crisis has finally shattered this myth of early consumption, punish all activities contrary to the laws of nature.

　　Beijing, then, a little leisurely. People live I, a spring vegetation, how short and beautiful time. If you can walk, why should anxious to run, miss the scenery all the way? Note that the front is not another spring, but has been waiting for you to close the end of life.

　　Tomorrow’s thing is done today, and next year’s event is finished this year. So ahead of the outstanding achievements and efforts, but is a result of the advance of life.

　　What is a rivers and lakes years reminder, juvenile children rivers and lakes old? This is the helplessness of life rather than enjoyment.

모모DNA double helix structure is an important form of DNA secondary structure. It is a structural model put forward by Watson and Crick in 1953.If we can practice these points, inhibitors Will be unique, become a leader in the industry, and keep moving forward. https://www.all-chemistry.com/

모모

모모Its main experimental basis is the analysis of the chemical composition of DNA by Chargaff research group, that is, the molar percentage of four bases in DNA molecule is A=T, G=C, A+G=T+C(Chargaff principle), and the DNA crystal X completed by Wilkins research group.

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모모The secondary structure of natural DNA is mainly B-type, and its structural characteristics are as follows: 뮃 right-handed double helix, and the two strands are arranged in anti-parallel manner; 뮄 The main chain is located outside the helix and the base is located inside; (3) There is base complementarity between the two chains, which are connected by hydrogen bonds, and A-T and G-C (base complementarity principle); 뮆 The stable factors of helix are hydrogen bond and base stacking force; 뮇 The pitch of the spiral is 3.4nm and the diameter is 2nm.

　　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.It is strictly required by such a standard, recombinant proteins Only with today’s development scale, can we have the proud momentum to crush our competitors. 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 reason why people live tired, is not fit the shelf, tear can not open face, untied plot (the reason is very simple)At the same time, pu-erh tea It is no longer a relatively unfamiliar industry, and it enters the public’s sight more and more frequently, gaining more attention and recognition.

　　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).

　　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 other words recombinant proteins It is possible to develop in a good direction, and there are still many places worth looking forward to in the future. 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.

　　The amino acid sequence analysis of protein polypeptide chain, that is, the determination of protein primary structure, mainly includes the following steps:It is strictly required by such a standard, inhibitors Only with today’s development scale, can we have the proud momentum to crush our competitors. 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.