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In chemistry, a Haworth projection is a common way of writing a structural formula to represent the cyclic structure of monosaccharides with a simple three-dimensional perspective. A Haworth projection approximates the shapes of the actual molecules better for furanoses —which are in reality nearly planar—than for pyranoses that exist in ...
The reaction creates a ring of carbon atoms closed by one bridging oxygen atom. The resulting molecule has a hemiacetal or hemiketal group, depending on whether the linear form was an aldose or a ketose. The reaction is easily reversed, yielding the original open-chain form. In these cyclic forms, the ring usually has five or six atoms.
In chemistry, a hexose is a monosaccharide (simple sugar) with six carbon atoms. [1] [2] The chemical formula for all hexoses is C 6 H 12 O 6, and their molecular weight is 180.156 g/mol. [3] Hexoses exist in two forms, open-chain or cyclic, that easily convert into each other in aqueous solutions. [4]
The reaction between C-1 and C-5 yields a six-membered heterocyclic system called a pyranose, which is a monosaccharide sugar (hence "-ose") containing a derivatised pyran skeleton. The (much rarer) reaction between C-1 and C-4 yields a five-membered furanose ring, named after the cyclic ether furan.
L-Ribose Fischer Projection. Ribose is a simple sugar and carbohydrate with molecular formula C 5 H 10 O 5 and the linear-form composition H−(C=O)−(CHOH) 4 −H. The naturally occurring form, d-ribose, is a component of the ribonucleotides from which RNA is built, and so this compound is necessary for coding, decoding, regulation and expression of genes.
If reaction is between the C-4 hydroxyl and the aldehyde, a furanose is formed instead. [1] The pyranose form is thermodynamically more stable than the furanose form, which can be seen by the distribution of these two cyclic forms in solution. [2] Formation of pyranose hemiacetal and representations of β-D-glucopyranose
Mannose is a dominant monosaccharide in N-linked glycosylation, which is a post-translational modification of proteins. It is initiated by the en bloc transfer on Glc 3 Man 9 GlcNAc 2 to nascent glycoproteins in the endoplasmic reticulum (ER) in a co-translational manner as the protein entered through the transport system.
In organic chemistry, a hemiacetal is a functional group the general formula R 1 R 2 C(OH)OR, where R 1, R 2 is a hydrogen atom or an organic substituent. They generally result from the nucleophilic addition of an alcohol (a compound with at least one hydroxy group) to an aldehyde (R−CH=O) or a ketone (R 2 C=O) under acidic conditions.