Biomacromolecule

Molecules existing in living cells

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Biomacromolecules refer to organisms somatic cell Protein nucleic acid , polysaccharide and other macromolecules. Each biological macromolecule has thousands to hundreds of thousands of atoms, and its molecular weight ranges from tens of thousands to millions. The structure of biological macromolecule is very complex, but its basic structural unit is not complex. Protein molecules are long chains of amino acids arranged in a certain order. amino acid Molecules are the constituent materials of most living materials, and there are dozens of different amino acid molecules. The vast majority of enzymes in the organism belong to proteins, which are indispensable for the organism to maintain normal metabolic function.^[1]

Chinese name: Biomacromolecule
Foreign name: biomacromolecule
Basic substances: Biomolecule

Kinetic energy: Biological function
Meaning: It refers to protein, nucleic acid, polysaccharide and other macromolecules existing in biological cells
Status: Important components of organisms

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one brief introduction
two Formation of biomacromolecules

brief introduction

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Biomacromolecule and low molecular weight Relative molecular weight Creatures of Organic compound In contrast, organic compounds with high relative molecular weight have higher material groups. They are polymerized from organic compounds with low relative molecular weight Multimolecular system 。 Most biological macromolecules are polymerized by simple composition structure. The composition unit of protein is amino acid, and the composition unit of nucleic acid is nucleotide ... such as amino acids and fatty acids Biomolecule Are substances closely related to life. They are the basic substances that constitute macromolecules. from Chemical structure In terms of protein α- L- Amino acid dehydration condensation Nucleic acid is made from purine and Pyrimidine base , and sugar D- Ribose Or 2- deoxidation -D-ribose and phosphoric acid are dehydrated and condensed. Polysaccharide is composed of monosaccharide It is made by dehydration and condensation. It can be seen from this that the chemical reactions from low molecular weight bio organic compounds to high molecular weight bio organic compounds are dehydration condensation reaction 。 It refers to various kinds of active ingredients molecular weight Up to tens of thousands or more Organic molecule 。 high Relative molecular weight The bio organic compounds (biomacromolecules) mainly refer to proteins, nucleic acids and hydrocarbons with high relative molecular weight. Common biological macromolecules include protein, nucleic acid Polysaccharide 。 This definition is only conceptual, which is opposite to biological macromolecules Small molecule Substances (carbon dioxide, methane, etc.) and Inorganic Quality.

Biomacromolecular conformation

In fact, biological macromolecules are characterized by their various biological activity And its role in biological metabolism. Biomacromolecules are the basic materials of life. For example: some polypeptide And some lipid substances molecular weight It did not reach an astonishing level, but it also showed important physiological activities in the life process. Same as ordinary biological macromolecules^[2] 。

Formation of biomacromolecules

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stay Primitive Earth Under the condition, there are two paths to dehydration synthesis To form high polymer : First, by heating Relative molecular weight Heating the component materials to dehydrate and polymerize; The second is utilize Existing on the primitive earth Dehydrating agent To condense. The former is often close to anhydrous volcano The latter can be carried out in the water environment.

All biomacromolecules can be synthesized from simple structures in the organism, and can also be decomposed into simple structures through decomposition in the organism, generally in the process of synthesis consume Energy, released during decomposition energy 。

Overview of biological macromolecules

Biomacromolecules are important components of organisms, which not only have biological functions, but also molecular weight It is large and its structure is complex. In addition to the main proteins and nucleic acids, there are also sugars, lipids and their combination products in biological macromolecules. as glycoprotein 、 Lipoprotein 、 Nucleoprotein Etc. Their molecular weight is often 100 or more times larger than that of ordinary inorganic salts. The molecular weight of proteins ranges from 10000 to tens of thousands, and that of nucleic acids reaches millions. The complex structure of these biological macromolecules determines their special properties, and their movement and changes in the body reflect important life functions. For example, carrying out metabolism to supply energy and material needed to maintain life, transmitting genetic information, and controlling embryo Differentiation, promoting growth and development, producing immune function, etc.

Research difficulties

The research of biological macromolecules has experienced a long history of nearly two centuries. Due to the complex structure of biological macromolecules and their denaturation easily affected by temperature, acid and alkali, the research work is very difficult. Before the end of the 20th century, the main research work was the extraction of biomacromolecules nature Chemical composition and preliminary structural analysis.

Early research achievements

Since the 1930s, when the cell theory was established, someone had studied proteins. Protein naming began in 1836, when the famous Sweden J. Berzelius, a chemist, and G.J. Mulder, a Dutch chemist who is studying egg protein compounds, proposed to name these compounds with "protein". And list it as Life system The most important substance in. By the beginning of the 20th century, 12 of the 20 amino acids that make up the protein had been found, and the rest were found in 1940. At the end of the 19th century, organic chemists began to explore the structure of proteins. German organic chemist E. Fischer cooperated with others to put forward the argument that peptide bonds between amino acids connect to form proteins. In 1907, Fischer synthesized a long chain of 18 peptides consisting of 15 glycines and 3 leucines. At the same time, J.D. Bernal and W.T. Astbury in the British school of crystal analysis used X-ray diffraction analysis Methods To analyze the structure of wool, hair and other proteins and prove that they are folded and curled fibrous substances. With the gradual deepening of research, scientists have found out that protein is the main component of muscle, blood, hair, etc., and has many functions.

Discovery of nucleic acids

Nucleic acid was discovered much later than protein. 24-year-old working in Germany in 1868 Switzerland Chemist F. Miescher extracted what was then called "nucleoplasm" from the patient's wound pus cells. This is the earliest discovery of nucleic acids, which was later recognized. later Corsaire (A. Kssel) and his two students, W. Jones and P.A. Levene, have figured out the basics of nucleic acids Chemical structure It is confirmed that nucleic acid is composed of many nucleotide A macromolecule of composition. Nucleotide is composed of base Ribose And phosphoric acid. There are 4 kinds of bases (adenosine, guanosine, cytosine and Thymine ）There are two kinds of ribose (ribose and deoxyribose). According to this, nucleic acids can be divided into two categories: ribonucleic acid (RNA) and Deoxyribonucleic acid (DNA)。 According to their rough analysis at that time, they believed that the amount of four bases in the nucleic acid was equal, so they incorrectly deduced that the basic structure of nucleic acid was that four nucleotides containing different bases were connected into tetranucleotides, and then polymerized into nucleic acids on this basis, which was the more famous "tetranucleotide hypothesis". This hypothesis has dominated the research of nucleic acid structure for about 20 years since the 1920s, and has played a considerable role in understanding the complex structure and function of nucleic acids Hindrance 。 Although nucleic acid was found in the nucleus at that time, because its structure was too simple, it was difficult to imagine what role it could play in the extremely complex and changeable genetic phenomenon. Even some scientists thought that protein might play a major role in heredity after the structure of protein was clarified at that time.

Clarification of enzyme

The explanation of enzyme is that in 1897, German chemist E. Buchner extracted from ground yeast cells alcohol fermentation The fermentation enzyme started. Bushner's research shows that the enzyme extracted from living body can work as well as in living body. It not only attacked the popular theory of vitality at that time, but also enabled biochemical research to understand the Chemical change Phase of. Later, British biochemist A. Harden and others made many researches on the specific chemical steps of alcohol fermentation. By the 1920s, a large number of experimental results showed that the two processes of yeast fermentation of sugar to produce alcohol and muscle contraction of sugar to lactic acid were basically the same, also known as Glycolysis 。 In the 1930s, after many scientists' research, German biochemists Krebs (H.A. Krebs) proposed the tricarboxylic acid cycle in which biological respiration finally produces CO2, H2O and energy (ATP). During this period, many scientists also studied the metabolism of fat and amino acids, as well as the mutual transformation of sugar, fat and protein in metabolism and their biosynthesis Etc. These processes are completed under the catalysis of enzymes.

Interaction between Inorganics and Biomacromolecules

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The interaction between inorganic substances and biological macromolecules is mainly reflected in the interaction between metal ions and their complexes and biological macromolecules. It mainly includes the probe and recognition of metal ions to biomacromolecules, the competitive reaction of ligands and biomacromolecules to metal ions, and the transfer of ions and electrons within or between biomacromolecules. When metal ions combine with biological macromolecules, obvious biochemical effects often occur. For example, some metal chlorides and gluconates can activate and inhibit the activity of glucose oxidase. The interaction of metal ions and their complexes with proteins mainly includes conformational changes caused by metal binding, and subsequent biological effects caused by association and assembly. In addition. The research on the interaction of metal ions and their coordination with DNA can help people understand the essence of life phenomena at the molecular level, and provide theoretical guidance for rational design and search for effective therapeutic drugs. If small molecules are used for transition Metal complex Interaction with macromolecular DNA can explore the structure, mechanism and function of macromolecular DNA^[2] 。

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