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The reaction often favors formation of the α-glycosidic bond as shown due to the anomeric effect. A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some compound such as an alcohol. A substance containing a glycosidic bond is a glycoside.
This can result in different regioselectivity depending on the acceptor resulting in products with different glycosidic linkages. One example is the Agrobacterium sp. β-glucosynthase, which forms a β-1,4-glycoside with glucose as the acceptor, but forms a β-1,3-glycoside with xylose as the acceptor.
The formation of a glycosidic linkage results in the formation of a new stereogenic centre and therefore a mixture of products may be expected to result. The linkage formed may either be axial or equatorial (α or β with respect to glucose). To better understand this, the mechanism of a glycosylation reaction must be considered.
A glycosyl acceptor is any suitable nucleophile-containing molecule that will react with a glycosyl donor to form a new glycosidic bond.By convention, the acceptor is the member of this pair which did not contain the resulting anomeric carbon of the new glycosidic bond.
The different types of lipid-linked oligosaccharide (LLO) precursor produced in different organisms.. N-linked glycosylation is the attachment of an oligosaccharide, a carbohydrate consisting of several sugar molecules, sometimes also referred to as glycan, to a nitrogen atom (the amide nitrogen of an asparagine (Asn) residue of a protein), in a process called N-glycosylation, studied in ...
Glycosylation also plays a role in cell-to-cell adhesion (a mechanism employed by cells of the immune system) via sugar-binding proteins called lectins, which recognize specific carbohydrate moieties. [2] Glycosylation is an important parameter in the optimization of many glycoprotein-based drugs such as monoclonal antibodies. [6]
Initially, about seven UDP-glucose molecules are added to each tyrosine residue by glycogenin, forming α(1→4) bonds. Once a chain of seven glucose monomers is formed, glycogen synthase binds to the growing glycogen chain and adds UDP-glucose to the 4-hydroxyl group of the glucosyl residue on the non-reducing end of the glycogen chain ...
The glycosidic bond is formed from a glycosyl donor and a glycosyl acceptor. There are four types of glycosidic linkages: 1, 2-trans-α, 1, 2-trans-beta, 1, 2-cis-α, and 1, 2-cis-beta linkages. 1, 2-trans glycosidic linkages can be easily achieved by using 2-O-acylated glycosyl donors (neighboring group participation).