Mannose is an organic compound with molecular formula CsixHtwelveOsix, molecular weight 180.156, colorless or white crystalline powder.It is a carbohydrate that plays an important role in human metabolism, especially in the glycosylation of specific proteins.[1]
On August 15, 2023, the academic journal Science Bulletin published research results showing that the scientific research team of Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences and Dalian Institute of Chemical Physics mixed high concentration carbon dioxide and other raw materials in a certain proportion in the reaction solution, and under the action of chemical catalysts and enzyme catalysts, four kinds of hexoses such as mannose were obtained。[4]
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Summary of reaction between mannose and various substances
one kindmonosaccharide。It is a component of many polysaccharides.withDissociative stateIt is found in the peel of some plants, such as citrus peel, peach, apple and other fruits with a small amount of free mannose, ivory palm, yeast, red algaeSerum globulin、Egg mucoidandMycobacterium tuberculosisGlycan containing D-mannose.[2]
Physicochemical properties
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Mannose is white crystal or crystal powder, sweet with bitter taste+29.3 ° (water);βThe melting point is 132 ℃ (decomposition), - 17 ° →+14.6 ° (water).Soluble in water, slightly soluble in ethanol.D-mannose andcalcium chlorideEasy to form crystalline compound CsixHtwelveOsix·CaCltwo·4HtwoO. And display complexVariable optical rotationeffect.D-mannose can be fermented by yeast.[3]
metabolize
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Mannose is not metabolized well in human body.Therefore, the process of mannose entering into carbohydrate metabolism after oral administration is not obvious. Even g mannose entering from the outside will be detected by tissues in the body.Use of radioactivity in mammalsMarkersIt was found that 90% of the mannose ingested would be discharged intact from the body through the urethra within 30-60 minutes.99% of the residue will be discharged in the next 8 hours.During this process, the blood sugar concentration will not increase significantly.[2]
etymology
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Mannose in English originates from manna, which is Israel in the BibleSinai PeninsulaGod's food: manna.
In reality, manna is the sweet secretion of some trees and shrubs.The white wax tree secretes this kind of thing.[2]
Physiological effect
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Mannose, the only glyconutrient used clinically, is widely distributed in body fluids and tissues, especially in nerves, skin, testes, retina, liver and intestines.It is directly used to synthesize glycoproteins and participate in immune regulation.Many diseases are caused by the lack of enzymes in mannose glycosylation.
Its physiological effects in human body are as follows:
Mannose receptorC-type is a kind of animal lectin, which can effectively and quickly identify mannose and fucose end glycoprotein to form an organic defense system.Generally speaking, the structure of mannose receptor is divided into the following parts: the N-terminal is rich in Cys region;139~192 amino acid region;CRD;Glycosylation sites;Cytoplasmic and transmembrane regions.
Relationship between lymphatic metastasis of liver cancer and mannose receptor:
Liver cancer is also a kind of cancer with high mortality rate, and tumor metastasis of liver cancer generally directly leads to the deterioration of patients' condition and even death.Generally speaking, there is a direct correlation and influence between the malignant degree of the tumor and the metastatic ability of the tumor. In a sense, mannose receptor is to improve the metastatic ability of liver cancer cells, thereby increasingCancer cell proliferationTo improve the malignant degree of liver cancer.Mannose receptor also plays the role of adhesion molecule in the process of cancer cell metastasis, and provides some help for cancer cell metastasis.Therefore, in order to effectively control the metastasis of liver cancer cells and the deterioration of liver cancer, it is necessary to control the relevant adhesion molecules, and the most effective way is to block the mannose receptor and other molecules.
Generally speaking, what can express mannose receptor in human body is the output lymphatic vessel. Generally, mannose receptor is not expressed in high endothelial vein.Through previous studies, it was found that during the process of cancer cell metastasis, the mannose receptor and L-selectin had a certain connection and effect, so thatlymphocyteIt can export lymph tissue, further let cancer cells interact with mannose receptors, so that cancer cells can quickly metastasize in lymphatic vessels.In previous studies on breast cancer, it was found that mannose receptors can effectivelyepithelial cellsThe decreased adhesiveness of tumor cells leads to the smooth metastasis of cancer cells.And in the mouse experiment, it was found that the loss of mannose receptor can indeed reduce the degree of metastasis of cancer cells in mice, not only reducing the metastasis of cancer cells to lymph, but also reducing the metastasis of normal cells to lymph.Through the clinical research of liver cancer cells, it is also proved that whether the expression of mannose receptor is really related to the lymphatic metastasis of cancer.This also shows that effectively and reasonably blocking the expression of mannose receptor can indeed play a considerable role in inhibiting cancer metastasis.[3]
