Polysaccharides

Polysaccharides is high-molecular optically active carbohydrates (molecular weight from a few thousands to millions), molecule which one consist of residues of monosaccharides (see). It is a colorless, amorphous substances, most of which are easily swells in water, forming a viscous colloidal solutions. Polysaccharides are widely distributed in nature (the most numerous is cellulose - part of the wood). Starch and some other polysaccharides are formed in plants during photosynthesis. At acid or enzymatic hydrolysis of polysaccharides broken down into the simple sugars monosaccharides.
In living organisms polysaccharides are energy reserve (glycogen in animals, starch plants), serve as supporting elements (chitin in insects and crustaceans, cellulose in plants). These polysaccharides, as mucopolysaccharides (see), are a natural anticoagulants (see) (for example, heparin), or perform some special functions. Polysaccharides, especially starch, are important parts of food products. Many polysaccharides used as raw materials: starch in food, pharmaceutical industry and others, cellulose - for the production of fibers. Physiologically active polysaccharides - heparin (see), dextrin, gums is used in medicine.
Cm. also Mucopolysaccharides, Carbohydrates.

Polysaccharides (synonym: complex sugar, polity, glikana) - carbohydrates, molecule which one consist of multiple residues (from two to several thousand) of the same or different monosaccharides or related substances (deoxysaccharides, amino sugars, uronic acids and so on).

the formula of polysaccharides

The General formula of the most common polysaccharides: CnH2mOm
. All of Peterhof built in the type of glycosides (see): the hydrogen atom in policealna the hydroxyl one molecule of monosaccharide is replaced with the second molecule of monosaccharide, the hydrogen atom in policealna the second hydroxyl molecule is replaced by a third molecule and so on
As a result, when any number monosaccharide residues in the molecule P. usually there is only one free polyacetylenes hydroxyl ("aldehyde", or regenerating start polyglycosides chain).
One polyglucoside circuit can be connected through oxygen his polyacetylenes hydroxyl to any intermediate monosaccharide residues other polyglycosides chain; thus there are extensive P.
Different polysaccharides differ in the degree of polymerization, ie, the number monosaccharide residues in the molecule; depending on this distinguished: a) oligosaccharides containing from 2 to 9 monosaccharide residues (disaccharides, trisaccharide and so on) with a small pier. weight, well-soluble in water, with a sweet taste - P. chromozone; b) higher polity, usually containing several hundreds and even thousands of residuals, high-molecular substances, poorly soluble or not soluble in water, not having sweet taste.
Different polysaccharides and availability of the same or different monosaccharide residues [gonopoliskiy (such as glycogen, fat otherwise cellulose, amiloza consist of glucose residues; chitin - of glucosamine; peckova acid - from the galacturonic acid) and heteropolysaccharides (for example, hemicellulose, Arabian gum, many bacterial polysaccharides)].
There is a direct polyglycosides circuit (as in amylose, cellulose) and in varying degrees, branched (amylopectin, glycogen) also shows differences P. Finally, polysaccharides are distinguished by the presence pyranose or furanone rings (inulin), α configuration monosaccharide residues (amylase), beta-configuration (cellulose) or those and other configurations (guaran) and the presence of certain glycosidic linkages connecting the first carbon atom of one of the residue with the fourth or other carbon atoms of other balance, for example links α-1,4 (amiloza), beta-1,4 (cellulose), α-1,6 (dextran), etc.
In many cases in molecules P. there are different glycosidic bonds. Origin polysaccharides divided into vegetable, animal and P. microorganisms (bacteria and fungi).
As polyglucoside, P. undergo hydrolysis - acid or enzymatic. As every monosaccharide remainder remain free alcohol hydroxyl acids and polysaccharides can form compounds of the type of simple and complex ethers of importance for the identification, establishment of the structure (methyl esters), as well as important in the practice of the substance (for example, ethers of cellulose).
Such higher P., as starch and a number of oligosaccharides (sucrose, lactose) have important nutritional value. Many P. play the role of energy reserves organisms: glycogen (see) in animals, starch and other polysaccharides in plants.
A number of polysaccharides [cellulose (cellulose) in plants and chitin some animals crustaceans, insects] plays an important supporting role. Many P., especially, the medicine polysaccharides (see)containing residues of amino sugars and often uronic acids, perform highly important [for example, heparin is a natural anticoagulant, hyaluronic acid (see) is the barrier function, mucopolysaccharides blood groups (so-called group-specific P.) and tissues determine their specificity]. Many P. possess antigenic (causing the immune system) properties (immunospecificity P.). A number of polysaccharides used as honey. drugs: dextran (see), heparin (see) and other
Many P. have a great technical value, such as cellulose, dextrins, pectin, representing derivatives polygalacturonases acid.