Important raw materials for forming articular cartilage tissue and joint lubrication materials
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Glucosamine is formedArticular cartilageIt is an important raw material for tissue and joint lubrication materials, providing joint lubrication and protection functions, and has the physiological activity of inhibiting the generation of free radicals and attacking joints.
Chinese name
Glucosamine
English name
glucosaminoglycan
definition
The product obtained after deacetylation of chitosan.It is a mixture of some molecules with different molecular weights and degrees of deacetylation.
Definition: The product obtained by deacetylation of chitosan.It is a mixture of some molecules with different molecular weights and degrees of deacetylation.
Glucosamines (GAGs) are unbranched polysaccharide chains composed of repeated disaccharide units.In repeated disaccharides, one of the two sugars is always an aminosugar (N-acetylglucosamine or N-acetylgalactose), which is sulfated in most cases.The other is usually uronic acid.Because most of their sugars have sulfate or carboxyl groups, glycosaminoglycans have a high negative charge.In fact, they are the most negatively charged molecules produced by animal cells.The glycosaminoglycans are mainly divided into four categories: (1) hyaluronic acid, (2) chondroitin sulfate and dermatan sulfate, (3) heparin sulfate, and (4) keratin sulfate.They are mainly distinguished by the type of sugar sugar connection and the number and location of sulfate groups.
Hyaluronic acid (hyaluronic acid) is a relatively simple glycosaminoglycan.It consists of a long chain consisting of up to 25000 repeating disaccharide units, each of which carries a negative charge.Like other glycosaminoglycans, one sugar monomer in each disaccharide unit is an amino sugar.Hyaluronic acid exists in different amounts in all tissues and fluids of adult animals, especially in early embryos.Hyaluronic acid is not a typical glycosaminoglycan, because it does not contain sulfate sugar, and all its disaccharide units are the same.At the same time, its chain length is huge, and it is usually not covalently linked with any core protein.In addition, other glycosaminoglycans are synthesized in cells and released through extracellular secretion, while hyaluronic acid is directly spun from the cell surface through the enzyme complex embedded in the cell membrane.
Due to the rigid chain of polysaccharides and their strong hydrophilicity, glycosaminoglycans cannot be folded into a compact spherical structure. On the contrary, they prefer to use a highly expanded conformation, which occupies a huge volume relative to its mass. Therefore, even at very low concentrations, glycosaminoglycans can form hydrated gels.
In connective tissue, the mass of glycosaminoglycan is usually less than 10% of the mass of protein. The extracellular matrix is almost completely composed of collagen, but glycosaminoglycan occupies most of the extracellular space.Therefore, glycosaminoglycan plays an effective role as "interstitial filler" in the extracellular matrix of connective tissue.Their high density negative charges attract a large number of cations, especially sodium ions with high permeability, resulting in a large amount of water being sucked into the matrix, which creates swelling pressure, which can be balanced by the tension of collagen fibers interwoven with proteoglycans.This matrix is tough, elastic and anti compression.For example, the cartilage matrix arranged on the knee joint can withstand hundreds of atmospheric pressures in this way.
Deficiency in glycosaminoglycan synthesis affects many different body systems.For example, in a rare human genetic disease, there is a serious defect in the synthesis of dermatan sulfate. The affected individuals are short in stature, aging in advance, and the skin, joints, muscles and bones are generally defective.
Applied discipline
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: Biochemistry and Molecular Biology (first-class discipline);Sugar (secondary discipline)
