Homoglycans
Homoglycans or Homopolysaccharides are contrary to the heteroglycans from similar monosaccharides structured polysaccharides , ie polysaccharides assembled from a single variety of simple sugars . The biochemically most important homoglycans are glycogen (self-synthesis, meat ), as well as starch ( grain ) and cellulose (as fiber , grass , lettuce ) from plants and chitin as a structural substance in arthropods and fungi .
Properties of some homoglycans
Glycogen is composed of glucose or maltose units (glucose dimer ); the main storage location is muscle and liver. Starch is divided into unbranched amylose and branched amylopectin . The amylose, the proportion of which is around 20%, consists of α-1-4-linked, non-branched glucose. The primary structure is a helix , the color changes to blue due to iodine storage . This is the amylose and thus strength proof. It is first broken down into disaccharide units (maltose) in the digestive tract . The amylopectin shows an average branch after about 25 glucose molecules. The linkage takes place via α-1-4 bonds, branches through an α-1-6 side chain with isomaltose as the basic element.
The cellulose, on the other hand, is linked β-1-4 and therefore can not be broken down by the human organism .
Representative
Homoglycans occur naturally in almost all living things and form structural (chitin, cellulose) and storage substances (starch, glycogen).
- Different homoglycans from bacteria
- Curdlan from Alcaligenes faecalis var. Myxogenes
- Dextran from Leuconostoc mesenteroides , Leuconostoc dextranicum and Lactobacillus hilgardii
- Glucuronan from Sinorhizobium meliloti
- Lentinan from Lentinus elodes
- Laevan from Alcaligenes viscosus , Zymomonas mobilis and Bacillus subtilis
- Mutan from Streptococcus mutans
- Pullulan from Aureobasidium pullulans
- Scleroglucan from Sclerotium rolfsii , Sclerotium delphinii and Sclerotium glucanicum
- Schizophyllan from Schizophyllum commune
- Cellulose from Acetobacter xylinum (and from plants )
- Different homoglycans from mushrooms
- Chitosan from Mucorales
- Chitin from various mushrooms and arthropods
- Pleurane from Pleurotus ostreatus
- Zymosan from yeast
- A homoglycan from Euglenophyceae and calcareous algae
- Different homoglycans from algae
- Chrysolaminarin from Laminaria sp.
- Laminarin from Laminaria sp.
- Different homoglycans from plants
Individual evidence
- ↑ Entry on homopolysaccharide (homoglycan) . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.H02856 Version: 2.1.5.