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Fucose
Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on ''N''-linked glycans on the mammalian, insect and plant cell surface. Fucose is the fundamental sub-unit of the seaweed polysaccharide fucoidan. The α(1→3) linked core of fucose is a suspected carbohydrate antigen for IgE-mediated allergy. Two structural features distinguish fucose from other six-carbon sugars present in mammals: the lack of a hydroxyl group on the carbon at the 6-position (C-6) (thereby making it a deoxy sugar) and the L -configuration. It is equivalent to 6-deoxy--galactose. In the fucose-containing glycan structures, fucosylated glycans, fucose can exist as a terminal modification or serve as an attachment point for adding other sugars. In human ''N''-linked glycans, fucose is most commonly linked α-1,6 to the reducing terminal β-''N''-acetylglucosamine. However, fucose at the non-reducing termini linked α-1,2 to galactose forms the H antigen, the substructure of the A an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexose
In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. The chemical formula for all hexoses is C6H12O6, and their molecular weight is 180.156 g/mol. Hexoses exist in two forms, open-chain or cyclic, that easily convert into each other in aqueous solutions. The open-chain form of a hexose, which usually is favored in solutions, has the general structure H–(CHOH)''n''−1–C(=O)–(CHOH)4−''n''–H, where ''n'' is 1, 2, or 3. Namely, five of the carbons have one hydroxyl functional group (–OH) each, connected by a single bond, and one has an oxo group (=O), forming a carbonyl group (C=O). The remaining bonds of the carbon atoms are satisfied by seven hydrogen atoms. The carbons are commonly numbered 1 to 6 starting at the end closest to the carbonyl. Hexoses are extremely important in biochemistry, both as isolated molecules (such as glucose and fructose) and as building blocks of other compounds such as starch, cellulose, and glycosides. Hexose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deoxy Sugar
Deoxy sugars are sugars that have had a hydroxyl group replaced with a hydrogen atom. Examples include: * Deoxyribose, or 2-deoxy-D-ribose, a constituent of DNA * Fucose, or 6-deoxy-L-galactose, main component of fucoidan of brown algae, and present in N-linked glycans * Fuculose, or 6-deoxy-L-tagatose, one of the important components of avian influenza virus particles * Rhamnose, or 6-deoxy-L-mannose, present in plant glycosides In ''Escherichia coli'' bacteria, deoxyribose sugars are synthesized via two different pathways - one pathway involves aldol condensation, whereas the other pathway is conversion of a ribose sugar into a deoxyribose sugar by means of changes on the nucleotide or nucleoside level. Deoxyribose is synthesized through the reduction of ribose. Deoxyribose is derived from the same precursor as ribose being that the reduction of the sugar with the extra hydroxyl group results in the deoxy-sugar, which has its hydroxyl group replaced with a hydrogen atom. D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Verotoxin-producing Escherichia Coli
Shigatoxigenic ''Escherichia coli'' (STEC) and verotoxigenic ''E. coli'' (VTEC) are strains of the bacterium ''Escherichia coli'' that produce Shiga toxin (or verotoxin). Only a minority of the strains cause illness in humans. The ones that do are collectively known as enterohemorrhagic ''E. coli'' (EHEC) and are major causes of foodborne illness. When infection, infecting the large intestine of humans, they often cause gastroenteritis, enterocolitis, and dysentery, bloody diarrhea (hence the name "enterohemorrhagic") and sometimes cause a severe complication (medicine), complication called hemolytic-uremic syndrome (HUS). Cattle is an important natural reservoir for EHEC because the colonised adult ruminants are asymptomatic. This is because they lack vascular expression of the target receptor for Shiga toxins. The group and its subgroups are known by #Names, various names. They are distinguished from other strains of intestinal pathogenic ''E. coli'' including enterotoxigenic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-linked Glycan
The terms glycans and polysaccharides are defined by IUPAC as synonyms meaning "compounds consisting of a large number of monosaccharides linked glycosidically". However, in practice the term glycan may also be used to refer to the carbohydrate portion of a glycoconjugate, such as a glycoprotein, glycolipid, or a proteoglycan, even if the carbohydrate is only an oligosaccharide. Glycans usually consist solely of O-glycosidic linkages of monosaccharides. For example, cellulose is a glycan (or, to be more specific, a glucan) composed of β-1,4-linked D-glucose, and chitin is a glycan composed of β-1,4-linked ''N''-acetyl-D-glucosamine. Glycans can be homo- or heteropolymers of monosaccharide residues, and can be linear or branched. Glycans and proteins Glycans can be found attached to proteins as in glycoproteins and proteoglycans. In general, they are found on the exterior surface of cells. O- and N-linked glycans are very common in eukaryotes but may also be found, although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dextrorotation And Levorotation
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circular birefringence and circular dichroism are the manifestations of optical activity. Optical activity occurs only in chiral materials, those lacking microscopic mirror symmetry. Unlike other sources of birefringence which alter a beam's state of polarization, optical activity can be observed in fluids. This can include gases or solutions of chiral molecules such as sugars, molecules with helical secondary structure such as some proteins, and also chiral liquid crystals. It can also be observed in chiral solids such as certain crystals with a rotation between adjacent crystal planes (such as quartz) or metamaterials. When looking at the source of light, the rotation of the plane of polarization may be either to the right (dextrorotatory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fucitol
Fucitol, also known as L-fucitol, 6-deoxy-L-galactitol, and (2''R'',3''S'',4''R'',5''S'')-hexane-1,2,3,4,5-pentol, is a sugar alcohol derived from fucoidan which is found in the North Atlantic seaweed ''Fucus vesiculosus'' or by the reduction of fucose. See also * Galactitol Galactitol (dulcitol) is a sugar alcohol, the reduction product of galactose. It has a slightly sweet taste. In people with galactokinase deficiency, a form of galactosemia, excess dulcitol forms in the lens of the eye leading to cataracts. Gala ... References External links * Sugar alcohols {{Alcohol-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digitalose
Digitalose is a deoxy sugar that is a component of various cardiac glycosides including thevetin and emicymarin. It was first reported in 1892 as being obtained by the hydrolysis of ''Digtalinum verum''. The chemical structure was first elucidated in 1943 by the German chemist Otto Schmidt. Chemically, it is a methyl ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ... of D-fucose. See also * Sarmentose, a related deoxy sugar References {{reflist Deoxy sugars Ethers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FUT8
Alpha-(1,6)-fucosyltransferase is an enzyme that in humans is encoded by the ''FUT8'' gene. This enzyme belongs to the family of fucosyltransferases. The product of this gene catalyzes the transfer of fucose from GDP-fucose to N-linked type complex glycopeptides. This enzyme is distinct from other fucosyltransferases which catalyze alpha1-2, alpha1-3, and alpha1-4 fucose addition. The expression of this gene may contribute to the malignancy of cancer cells and to their invasive and metastatic capabilities. Alternatively spliced variants encoding different isoforms have been identified. Kyowa Hakko Kirin's "Potelligent" platform uses a CHO cell line in which ''FUT8'' has been knocked out to make afucosylated monoclonal antibodies Afucosylated monoclonal antibodies are monoclonal antibodies engineered so that the oligosaccharides in the Fc region of the antibody do not have any fucose sugar units. When antibodies are afucosylated, antibody-dependent cellular cytotoxicity (ADC .... ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Afucosylated Monoclonal Antibodies
Afucosylated monoclonal antibodies are monoclonal antibodies engineered so that the oligosaccharides in the Fc region of the antibody do not have any fucose sugar units. When antibodies are afucosylated, antibody-dependent cellular cytotoxicity (ADCC) is increased. Background Most approved monoclonal antibodies are of the IgG1 isotype, where two N-linked biantennary complex-type oligosaccharides are bound to the Fc region. The Fc region exercises the effector function of ADCC through its interaction with leukocyte receptors of the FcγR family. ADCC is important in the efficacy of cancer antibodies, but with many approved cancer antibodies there is less ADCC than could be desired due to nonspecific IgG competing with the drugs for binding to FcγIIIa on natural killer cells. Afucosylated monoclonal antibodies overcome this problem through improved FcγIIIa binding. Approaches The Swiss company GlycArt Biotechnology developed a system using CHO cells, where the cells were engineer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Killer Cell
Natural killer cells, also known as NK cells or large granular lymphocytes (LGL), are a type of cytotoxic lymphocyte critical to the innate immune system that belong to the rapidly expanding family of known innate lymphoid cells (ILC) and represent 5–20% of all circulating lymphocytes in humans. The role of NK cells is analogous to that of cytotoxic T cells in the vertebrate adaptive immune response. NK cells provide rapid responses to virus-infected cell and other intracellular pathogens acting at around 3 days after infection, and respond to tumor formation. Typically, immune cells detect the major histocompatibility complex (MHC) presented on infected cell surfaces, triggering cytokine release, causing the death of the infected cell by lysis or apoptosis. NK cells are unique, however, as they have the ability to recognize and kill stressed cells in the absence of antibodies and MHC, allowing for a much faster immune reaction. They were named "natural killers" because ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fucosylation
Fucosylation is the process of adding fucose sugar units to a molecule. It is a type of glycosylation. It is important clinically, and high levels of fucosylation have been reported in cancer. In cancer and inflammation there are significant changes in the expression of fucosylated molecules. Therefore, antibodies and lectins that are able to recognize cancer associated fucosylated oligosaccharides have been used as tumor markers in oncology. It is performed by fucosyltransferase enzymes. Fucosylation has been observed in vertebrates, invertebrates, plants, bacteria, and fungi A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from .... It has a role in cellular adhesion and immune regulation. Fucosylation inhibition applications are being explored for a range of clinical application incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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