Amino sugar

Amino sugars are monosaccharides ( simple sugar ) in which one or more hydroxy (-OH) is formally replaced by an amino group (-NH2). Free amino sugars are strongly basic and do not occur in nature; the monosaccharides are always components of glycosides and polymeric substances. As components of different, often essential biomolecules are essential for many key chemical processes and molecular structures in nature.

If the nitrogen bonded to the carbon atom of the anomeric center of a monosaccharide, as it is called in question amino sugar glycosylamine, otherwise it is called aminodeoxy.

This substance group was discovered in 1875 by the young physician Georg Ledderhose when he einkochte scissors and a tank recently ate lobster in hydrochloric acid and then glittering crystals discovered (D - glucosamine hydrochloride). The following year saw the first description, in 1903 the first synthesis ( by Fischer and Leuchs ), 1914 Phoebus Levene discovered and FB La Forge D- galactosamine. The detection of amino sugars in the influenza virus occurred in 1947 ( by CA Knight).

• 2.1 biosynthesis
• 2.2 laboratory synthesis

Function and meaning

In nature

Amino sugars are in various organisms as part of their cell structure of meaning: they consolidate at about bacteria murein cell wall function in arthropods and fungi as a building block of chitin and put in many higher organisms, the group of glycosaminoglycans as fibrous materials, components of cell membranes and the ground substance of the extracellular matrix, also are present in blood and milk. General apply 2-deoxy- 2-amino- aldoses such as D- glucosamine or D- galactosamine as the main amino sugar. But even with nucleotides encoding the basic building blocks of DNA, is substituted glycosylamines.

Because of their amino groups also provide amino sugar a relevant factor for the nitrogen content of soils is: an estimated 5-10% of soil N to go back on it, it comes from the majority of dead microorganisms, whereas plants do not produce amino sugar in significant quantities. In intensively farmed soils of the Aminozuckeranteil is measurable reduced because the bacterial synthesis decreases significantly as a result of industrial land use; also occur between different degrees cultivated soils differences in the proportion of certain amino sugars ( between those of bacterial origin, the concentration of more drops due to agricultural use, and those chitin entstamme ends ), whereby the relation between the two groups can be applied as an indicator of land use influences.

Use

A series of glycosidically linked amino sugars are characteristic of aminoglycosides, which thus act as antibiotics on protein synthesis of bacteria that then proteins nonsensical composition are formed. In addition, sialic acid analogues are used as Neuramidasehemmer to combat viral diseases such as influenza, but these are even no sugar. Furthermore, the physiologically cofactor formed in the mast cells of the anticoagulant, antithrombin III, heparin is used as anticoagulant.

With the Amadori rearrangement can be derived from aldose N- glucosides corresponding ketose N- glucosides win, which are important intermediates in the production of osazones, Osonen, quinoxalines and the vitamins riboflavin ( B2), and folic acid (B9 ) are.

Since amino sugars have a particularly strong magnetic coupling has also been proposed, it - to be used as source for the metal coordination centers synthetic catalysts - in place of the previously used proteins.

Chemistry

Free amino sugars react strongly basic, which is why they are acetylated in living organisms. Naturally are amino sugars, especially of hexoses common, which include, mannose, glucose (dextrose ), and galactose. Since the hydroxyl group of the C2 atom is replaced in favor, frequently gives rise to 2-amino- hexoses: Sun formed about from glucose, glucosamine, mannosamine and mannose from the galactose from a galactosamine.

Biosynthesis

The biosynthesis of the amino sugar extending via transamination, in which the amino group is derived from the amino acid glutamine. Glucose- 6-phosphate, hexose - transaminase is aminated to D-glucosamine -6-phosphate, for example, by the enzyme. The Glucosaminphosphat formed may be converted with the aid of a transacetylase into the N - acetyl derivative. After conversion to 1- phosphate that is activated by reaction with UTP and subsequently incorporated into various polymer compounds.

Laboratory synthesis

There are different ways to produce aminosugar. A method is a ring-closing reaction aldol type between dialdehydes and nitroalkanes. Thus, for example sucrose first then the nitro group can be reduced to the amino group with lead (IV ) acetate and acetic acid in the Ring of fructofuranose subunit cleaved oxidatively, that then closed again via reaction with nitromethane under presence of sodium methoxide and methanol.

A recent synthetic route is the aminodeoxy of 1-hydroxy -1 ,2- benziodoxol -3 ( 1H)-one -1-oxide ( " IBX " ) mediated presentation of glycals.