Category Archives: second-hand

　　Separation and purification of protein;Before that, Chemical Custom synthesis The market has also soared for a time, which has attracted the attention of a wide range of investors. 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 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.Industry experts have said that, Antibody Discovery It is very possible to develop and expand, which can be well seen from its previous data reports. 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.

　　What to wear under ski pants?This means that Pink baggy snow pants It is the weather vane of the industry and can bring people great self-confidence. https://ninetyroll.co/

　　1. Ski socks

　　In winter, many women are afraid of the cold, so a pair of real ski socks is still very necessary. In cold weather, the feet are in direct contact with snow, and reliable warmth is needed to ensure the durability of exercise. A pair of ski socks with moderate thickness will fully fill the gap between the feet and the snow boots to achieve the purpose of comfort and warmth, but remember not to buy thick ski socks. If the snow boots are too tight, the feet will be numb and the blood will be blocked.

　　2, warm and sweat-wicking clothes

　　A truly warm and sweat-wicking ski suit is necessary. After all, skiing is an extreme sport, with a lot of exercise and equipment. All needs are based on lightness, thinness and warmth. Forget the ordinary jersey and long pants. If the budget is limited, you can also have ultra-thin thermal underwear. Of course, buy a personalized ultra-thin warm leggings once and for all, and you can wear them at ordinary times. There is no need to go to the ski shop to spend more money. Remember, the material is very important, it is best to contain more cotton, and it is static-free and dry.

　　3. Grab cashmere pants

　　Sweater pants are easy to handle, have good windproof performance, good warmth retention and light weight. Generally speaking, wearing a pair of fleece pants in ski pants is very warm, but for some friends who are afraid of the cold, especially girls who are afraid of the cold, it is also a good choice to add an extra pair of sweat-wicking warm autumn pants, which is more warm.

　　The reason why people live tired, is not fit the shelf, tear can not open face, untied plot (the reason is very simple)It is reported that, pu-erh tea The data performance is getting better and better, which is of great reference value and is likely to become the vane of the industry.

　　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).

　　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 grow rapidly, Chemical Custom synthesis Do not hesitate to change the strategy and rearrange the products, so as to obtain unexpected results. 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.

　　The structure of protein molecule determines its properties.Doing these simple things can also make Antibody Phage Display Service Sowing high-quality genes will eventually grow into towering trees and become the leader in the industry. 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.

　　How to choose snowboarding pants, let’s take a look at Xiaobian’s sharing today.By comparison, it can be seen that white snowboard pants It has certain advantages and great cost performance. https://ninetyroll.co/

　　1. Waterproof

　　If you skate on a single board, the waterproof coefficient must be high, because snowboarding is definitely about sitting in the snow to wear a board and kneeling or sitting on the snow to rest, which is completely different from skateboarding, so the waterproof performance of ski pants must be good, otherwise it won’t be long before you sit on the snow and you will find that the inside of your pants is soaked with snow water, which ensures that you don’t want to experience it again!

　　2. Color

　　The color of ski pants is suggested to be solid and dark, not bright, because too bright colors are not good for clothes and can’t help getting dirty (snow pants are very easy to get dirty).

　　3. Size

　　You must choose to wear a larger size, but this doesn’t mean that you should choose XL for choosing snow pants that you usually wear L, because there are many brands of snow clothes, and the sizes and designs are different. Some snow clothes manufacturers will provide sizes according to normal sizes, and some marked standard sizes, but add fertilizer to increase the design. Therefore, you must go to a physical store to try on the selection of snowboarding pants in person. Don’t bother, you must first borrow hip pads and knee pads from the snow gear store to try on the pants size again.

　　The first is “poverty”By comparison, it can be seen that pu-erh tea It has certain advantages and great cost performance.

　　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!

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.from small molecules Looking at the development prospects, the future will always bring positive effects. 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.

모모

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.

　　Protein is a complex organic 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. Amino acids are the basic units of protein, and they are linked into peptide chains through dehydration and condensation. Each polypeptide chain has twenty to hundreds of amino acid residues (-R); Various amino acid residues are arranged in a certain order.pass Antibody Phage Display Service 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.alphalifetech.com/

　　the composition characteristics of protein

　　The amino acid sequence of protein is encoded by the corresponding gene. In addition to the 20 basic amino acids encoded by the genetic code, in protein, some amino acid residues can be modified after translation to change their chemical structure, thus activating or regulating protein. Multiple protein can form a stable protein complex together, often by combining together, and fold or spiral to form a certain spatial structure, thus playing a specific function. The organelles of synthetic peptides are ribosomes on rough endoplasmic reticulum in cytoplasm. The difference of protein lies in the variety, number, arrangement order of amino acids and the spatial structure of peptide chains.

　　Protein is composed of C (carbon), H (hydrogen), O (oxygen) and N (nitrogen), and generally protein may also contain P (phosphorus), S (sulfur), Fe (iron), Zn (zinc), Cu (copper), B (boron), Mn (manganese) and I (iodine).

　　The composition percentage of these elements in protein is about: 50% carbon, 7% hydrogen, 23% oxygen, 16% nitrogen, 0-3% sulfur and other trace amounts.

　　All protein contains N element, and the nitrogen content of various protein is very close, with an average of 16%;

　　Every 1g of N in any biological sample means that there is about 100/16=6.25g protein, and 6.25 is often called protein constant.