Chitin, polysaccharide

Polysaccharide chitin composing shells of crabs and similar creatures produced from modified glucose... 

Monosaccharides may possess functionalities other than hydroxyls. Amino sugars are aldoses or ketoses which have a hydroxyl group replaced by an amino functionality. 2-Amino-2-deoxy-glucose is one of the most abundant amino sugars it is a constituent of the polysaccharide chitin. It also appears in mammalian glycoproteins, linking the sugar chain to the protein. Monosaccharides may also be substituted with sulfates and phosphates. Furthermore, deoxy functions can often be present, and important examples of this class of monosaccharides are L-fucose and L-rhamnose. 

Fungal cell walls are composed primarily of the highly crystalline polysaccharides, chitin and )8-glucan, and various nonhydrolyzable melanins (Peberdy, 1990). Section 8.07.5.4 describes the structure and decomposition of chitin. While chitin has been well studied, very little is known about the structure or in situ decomposition of melanins (Butler and Day, 1998). However, melanins are thought to be a possible humus precursor because of their similarities with humic acids (Saiz-Jimenez, 1996). 

They are cell-wall constituents, non-cell-wall constituents, and storage materials in algae. In microorganisms, they may be cellular or extracellular constituents. The polysaccharide chitin is a structural component in the exoskeletons of crustaceans and insects. The greatest amount of polysaccharides is found in plant cell walls (higher plants, algae, and fungi). 

This chapter will give you an overview of recent approaches for drug development, focusing on the function and roles of carbohydrates. O Section 2 will outline the biochemical functions of polysaccharide (neutral polysaccharide, chitin and chitosan, glycosaminoglycan, and synthetic polysaccharides) and glycopolymers and the perspectives of their medicinal/medical use. O Section 3 will outline recent biopharmaceutical research and development, utilizing... 

Mammals rely on bones and muscles, which are made primarily of proteins, to give their bodies structure and support. However, insects and crustaceans, such as crabs and lobsters, rely on hard shells made of the polysaccharide chitin for structure. 

Cellulose is a polysaccharide found in plant cell walls. Cellulose forms the fibrous part of the plant cell wall. In terms of human diets, cellulose is indigestible, and thus forms an important, easily obtained part of dietary fiber. As compared to starch and glycogen, which are each made up of mixtures of a and (3 glucoses, cellulose (and the animal structural polysaccharide chitin) are made up of only (3 glucoses. The three-dimensional structure of the structural polysaccharides is thus constrained into straight microfibrils by the uniform nature of the glucoses, which resist the actions of enzymes (such as amylase) that breakdown storage polysaccharides (such a starch). 

Reflect and Apply Why is the polysaccharide chitin a suitable material for the exoskeleton of invertebrates such as lobsters What other sort of material can play a similar role ... 

Fungi produce the polysaccharide chitin as part of their cell wall. This is a polymer of JV-acetyl glucosamine which can be deacetylated to form chitosan. The chitosan can be treated with nitrous acid to form 2,5-anhydromannose which can be estimated colorimetrically (Figure 5.5). The test takes five hours but is not widely used as any insect debris interferes with it, and it is not suitable for estimating fungi in any plant products high in sugar amines. 

Kurita, K. 2001. Controlled fimctionaUzation of the polysaccharide chitin. Prog Polym Sci. 26 1921—1971. 

Hudson, S.M. and Smith, C. 1998. Polysaccharide Chitin and chitosan Chemistry and technology of then-use as structural materials. In Kaplan, D.L. (ed.). Biopolymers from Renewable Resources. Springer -Verlag, New York, pp. 96-118. 

Polysaccharides Reserve and Structural Forms Energy Storage Compounds Derived from Sugars Structural Carbohydrates Callose Pectins Plant Gums Algal Polysaccharides Chitin... 

Hudson SM, Smith C (1998) Polysaccharide chitin and chitosan chemistry and technology of their use as structural materials. In Kaplan DL (ed) Biopol)oners from renewable resources. Springer, New York, pp 96-118... 

Occurs in the skeletal polysaccharide chitin of insects, Crustacea and fimgi. Needles from EtOH. M.p. 110 decomp. Sol. HgO, hot MeOH. Spar. sol. EtOH. Insol. EtgO, CHCSg. 

Fungal polysaccharides Chitin, scleroglucan, lentinan, schizophyllan krestin, galactofuranose... 

Kurita K. Controlled functionalisation of the polysaccharide chitin. Prog. Polym. Sci. 26 (2001) 1921. 

---