Carbohydrate chemistry

German chemist (1852–1919)

thumb|upright=1.5|3D structure of cellulose, a [[beta-glucan polysaccharide]] thumb|class=skin-invert-image|upright=1.5|Amylose is a linear [[polymer of glucose mainly linked with α(1→4) bonds. It can be made of several thousands of glucose units. It is one of the two components of starch, the other being amylopectin.]]

Monosaccharides (from Greek monos: single, sacchar: sugar), also called simple sugars, are a class of organic compounds usually with the formula (CH2O)x. By definition they have two or more carbon-carbon bonds. More specifically, they are classified as polyhydroxy aldehydes or polyhydroxy ketones with the respective formulas or respectively. Monosaccharides can be classified by the number x of carbon atoms they contain: triose (3), tetrose (4), pentose (5), hexose (6), heptose (7), and so on.

thumb|287x287px|Sucrose, a disaccharide formed from condensation of a molecule of glucose and a molecule of fructose A disaccharide (also called a double sugar or biose) is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars soluble in water. Three common examples are sucrose, lactose, and maltose.

thumb|right|N-linked protein glycosylation (N-glycosylation of N-glycans) at Asparagine|Asn residues (Asn-x-Ser/Thr motifs) in glycoproteins.

thumb| Salicin, a glycoside related to [[aspirin ]] thumb|right|Chemical structure of oleandrin, a [[cardiac glycoside ]]

An oligosaccharide (; ) is a saccharide polymer containing a small number (typically three to ten) of monosaccharides (simple sugars). Oligosaccharides can have many functions including cell recognition and cell adhesion.

thumb|right|350px|Glycolipid

covalent bond joining a sugar molecule to another group

projection formula in which vertically drawn bonds are considered to lie below the projection plane and horizontal bonds to lie above that plane

Glycosylation is the reaction in which a carbohydrate (or 'glycan'), i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule (a glycosyl acceptor) in order to form a glycoconjugate. In biology (but not always in chemistry), glycosylation usually refers to an enzyme-catalysed reaction, whereas glycation (also 'non-enzymatic glycation' and 'non-enzymatic glycosylation') may refer to a non-enzymatic reaction.

projection formula in which the ring is drawn as if planar and the substituents points straight up or straight down perpendicular to the ring

thumb|235 px|Neuraminidase (GH34) ribbon diagram. An analog of its neuraminic acid substrate, used as an inhibitor drug, is the small white and red molecule in the center. thumb|235 px|N-Acetylneuraminic acid Exo-α-sialidase (, sialidase, neuraminidase; systematic name acetylneuraminyl hydrolase) is a glycoside hydrolase that cleaves the glycosidic linkages of neuraminic acids:

thumb|160px|Beta--fructofuranose A furanose is a collective term for carbohydrates that have a chemical structure that includes a five-membered ring system consisting of four carbon atoms and one oxygen atom. The name derives from its similarity to the oxygen heterocycle furan, but the furanose ring does not have double bonds.

In carbohydrate chemistry, anomers () are specific types of stereoisomers found in sugars.

In organic chemistry, pyranose is a collective term for saccharides that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom (a heterocycle). There may be other carbons external to the ring. The name derives from its similarity to the oxygen heterocycle pyran, but the pyranose ring does not have double bonds. A pyranose in which the anomeric (hydroxyl group) at C(l) has been converted into an OR group is called a pyranoside. {| class="wikitable float-right" style="text-align:center; font-size:90;" |- | class="hintergrundfarbe6" colspa

any of the N-acylneuraminic acids and their esters and other derivatives of the alcoholic hydroxy groups

In stereochemistry, mutarotation is the change in optical rotation of a chiral material in a solution due to a change in proportion of the two constituent anomers (i.e. the interconversion of their respective stereocenters) until equilibrium is reached. Cyclic sugars show mutarotation as α and β anomeric forms interconvert. The optical rotation of the solution depends on the optical rotation of each anomer and their ratio in the solution.

sugars that contain free OH group at the anomeric carbon atom

{| | 300px |- style="text-align: center;" | 140px |- | Chemical structures of digoxin (top) and its aglycone digoxigenin (bottom) |} An aglycone (aglycon or genin) is the chemical compound remaining after the glycosyl group on a glycoside is replaced by a hydrogen atom. For example, the aglycone of a cardiac glycoside would be a steroid molecule.

class of enzymes

thumb|Most glycosyltransferase enzymes form one of two folds: GT-A or GT-B Glycosyltransferases (GTFs, Gtfs) are enzymes (EC 2.4) that establish natural glycosidic linkages. They catalyze the transfer of saccharide moieties from an activated nucleotide sugar (also known as the "glycosyl donor") to a nucleophilic glycosyl acceptor molecule, the nucleophile of which can be oxygen- carbon-, nitrogen-, or sulfur-based.

class of antibiotic drugs

group of compounds

chemical reaction

class of antiviral drugs targeted at influenza

stereoelectronic effect, tendency of heteroatomic substituents adjacent to a heteroatom within a cyclohexane ring to prefer the axial orientation instead of the less hindered equatorial orientation that would be expected from steric considerations

rearrangement reaction

Glycomics is the comprehensive study of glycomes (the entire complement of sugars, whether free or present in more complex molecules of an organism), including genetic, physiologic, pathologic, and other aspects. Glycomics "is the systematic study of all glycan structures of a given cell type or organism" and is a subset of glycobiology. The term glycomics is derived from the chemical prefix for sweetness or a sugar, "glyco-", and was formed to follow the omics naming convention established by genomics (which deals with genes) and proteomics (which deals with proteins).

chemical reaction

substitution reaction of a glycosyl halide with an alcohol to give a glycoside

thumb|class=skin-invert|right|General chemical structure of a monogalactosyl diacylglycerol (MGDG), a prevalent type of galactolipid. R1 and R2 are fatty chains. Galactolipids are a type of glycolipid whose sugar group is galactose. They differ from glycosphingolipids in that they do not have nitrogen in their composition.

chemical reaction

addition reaction of carbonyl compounds and cyanide

thumb|right|100px|Glucal, the glycal formed from glucose Glycal is a name for cyclic enol ether derivatives of sugars having a double bond between carbon atoms 1 and 2 of the ring. The term "glycal" should not be used for an unsaturated sugar that has a double bond in any position other than between carbon atoms 1 and 2.

organic reaction

Saccharification is a term in biochemistry for denoting any chemical change wherein a monosaccharide molecule remains intact after becoming unbound from another saccharide. For example, when a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose).

biochemical technique

chemical reaction

Fucosylation is the process of adding fucose sugar units to a molecule. It is a type of glycosylation.