Polysaccharide
This carbohydrate can react with water (hydrolysis) using amylase enzymes as catalyst, which produces constituent sugars (monosaccharides or oligosaccharides).
When the repeating units in the polymer backbone are six-carbon monosaccharides, as is often the case, the general formula simplifies to (C6H10O5)n, where typically 40 ≤ n ≤ 3000.
Starch (a polymer of glucose) is used as a storage polysaccharide in plants, being found in the form of both amylose and the branched amylopectin.
[6] It has many uses such as a significant role in the paper and textile industries and is used as a feedstock for the production of rayon (via the viscose process), cellulose acetate, celluloid, and nitrocellulose.
The main action of dietary fiber is to change the nature of the contents of the gastrointestinal tract and how other nutrients and chemicals are absorbed.
[8][9] Soluble fiber binds to bile acids in the small intestine, making them less likely to enter the body; this, in turn, lowers cholesterol levels in the blood.
Glycogen is found in the form of granules in the cytosol/cytoplasm in many cell types and plays an important role in the glucose cycle.
[citation needed] In the liver hepatocytes, glycogen can compose up to 8 percent (100–120 grams in an adult) of the fresh weight soon after a meal.
The amount of glycogen stored in the body—especially within the muscles, liver, and red blood cells[18][19][20]—varies with physical activity, basal metabolic rate, and eating habits such as intermittent fasting.
[24] Furthermore, galactogen serves as an energy reserve for developing embryos and hatchlings, which is later replaced by glycogen in juveniles and adults.
These hydrogel structures can be designed to release particular nanoparticle pharmaceuticals and/or encapsulated therapeutics over time or in response to environmental stimuli.
[27] Inulin is a naturally occurring polysaccharide complex carbohydrate composed of fructose, a plant-derived food that human digestive enzymes cannot completely break down.
[28] Arabinoxylans are found in both the primary and secondary cell walls of plants and are the copolymers of two sugars: arabinose and xylose.
Its breakdown may be catalyzed by enzymes called chitinases, secreted by microorganisms such as bacteria and fungi and produced by some plants.
If chitin is detected, they then produce enzymes to digest it by cleaving the glycosidic bonds in order to convert it to simple sugars and ammonia.
The capsule cloaks antigenic proteins on the bacterial surface that would otherwise provoke an immune response and thereby lead to the destruction of the bacteria.
[37] Bacteria and many other microbes, including fungi and algae, often secrete polysaccharides to help them adhere to surfaces and to prevent them from drying out.
[39] This makes various liquids used in everyday life, such as some foods, lotions, cleaners, and paints, viscous when stationary, but much more free-flowing when even slight shear is applied by stirring or shaking, pouring, wiping, or brushing.
[citation needed] Aqueous solutions of the polysaccharide alone have a curious behavior when stirred: after stirring ceases, the solution initially continues to swirl due to momentum, then slows to a standstill due to viscosity and reverses direction briefly before stopping.
This recoil is due to the elastic effect of the polysaccharide chains, previously stretched in solution, returning to their relaxed state.
Polysaccharides also play an important role in formation of biofilms and the structuring of complex life forms in bacteria like Myxococcus xanthus[5].
The enzymes that make the A-band (homopolymeric) and B-band (heteropolymeric) O-antigens have been identified and the metabolic pathways defined.
The pel and psl loci are two recently discovered gene clusters that also encode exopolysaccharides found to be important for biofilm formation.
Rhamnolipid is a biosurfactant whose production is tightly regulated at the transcriptional level, but the precise role that it plays in disease is not well understood at present.
Protein glycosylation, particularly of pilin and flagellin, became a focus of research by several groups from about 2007, and has been shown to be important for adhesion and invasion during bacterial infection.
[42] Polysaccharides with unprotected vicinal diols or amino sugars (where some hydroxyl groups are replaced with amines) give a positive periodic acid-Schiff stain (PAS).
Due to the covalent attachment of methyl-, hydroxyethyl- or carboxymethyl- groups on cellulose, for instance, high swelling properties in aqueous media can be introduced.
