2. NAME- MAINAK CHAKRABORTY
PROGRAM- B.Tech (BIOTECHNOLOGY)
COURSE NAME- Term Paper
COURSE CODE- BTTP100
TOPIC- BIOMACROMOLECULE
POLYSACCHARIDES
MENTOR- Dr. ANIRBAN RAY
ENROLLMENT No.- A91704115037
YEAR- 2015-’19
3. INTRODUCTION:
Polysaccharide is a kind of Carbohydrate.
A carbohydrate is a biological molecule consisting of carbon (C), hydrogen (H)
and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in
water); in other words, with the empirical formula Cm(H2O)n (where m could be
different from n). Some exceptions exist; for example, deoxyribose, a sugar
component of DNA, has the empirical formula C5H10O4. Carbohydrates are
technically hydrates of carbon; structurally it is more accurate to view them as
polyhydroxy aldehydes and ketones. Carbohydrates are the main sources of
strength in any living organism.
DEFFINATION:
Optically active, polyhydroxy aldehydes and ketones or those components which
give polyhydroxy aldehydes and ketones by hydro-synthesis, those are called
Carbohydrates
• Carbohydrates have many uses in our daily life, like—
1. Most of our daily foods contain carbohydrate like ‘starch’.
2. Linen, rayon which are the raw materials for textile industries are made of
cellulose etc.
4. Figure 1
Lactose is a disaccharide found in
milk. It consists of a molecule of D-
galactose and a molecule of D-
glucose bonded by beta-1-
4 glycosidic linkage
5. Basically carbohydrates are two types—
SUGAR: Those carbohydrates which are colloidal, sweet in taste & soluble in
water are called sugar carbohydrates. Monosaccharides & Oligosaccharides
are sugar carbohydrates. E.g. Glucose, Fructose etc.
NON-SUGAR: Those carbohydrates which are non-colloidal, not sweet in
taste & insoluble or semi-soluble in water are called non-sugar carbohydrates.
Polysaccharides are non-sugar carbohydrates. E.g. Starch, Cellulose etc.
Classification of carbohydrates:
1) Monosaccharides (monoses or glycoses): Trioses, Tetroses,
Pentoses, Hexoses
2) Oligosaccharides: Di, tri, tetra, penta, up to 9 or 10 most important are
the disaccharides
3) Polysaccharides or glycans: a) Homopolysaccharides,
b) Heteropolysaccharides
6. As it is adhered by the supervisor, that I have to make a project on Chemistry of
Polysaccharides, so it is underneath:
POLYSACCHARIDES: Polysaccharides (Polymeric Carbohydrate
Molecule) are Natural Condensation Polymer composed of long chain of
Monosaccharides.
Polysaccharides are often quite heterogeneous, containing slight modifications of the
repeating unit. Depending on the structure, these macromolecules can have distinct
properties from their monosaccharide building blocks. They may be amorphous or
even insoluble in water. When all the monosaccharides in a polysaccharide are the same
type, the polysaccharide is called a homopolysaccharide or homoglycan, but when more
than one type of monosaccharide is present they are called Heteropolysaccharides or
Heteroglycans . When the repeating units in the polymer backbone are six-carbon
Monosaccharides, the general formula simplifies to (C6H10O5) n
Characteristics:
1. Polymers (MW from 200,000).
2. White and amorphous products (glassy).
3. Not sweet.
4. Not reducing; do not give the typical aldose or ketose reactions.
5. Form colloidal solutions.
8. Mainly Polysaccharides are two types-
1. Homosaccharides: These polymers composed of a single type sugar monomers.
These carbohydrates are three types-
Glucosan: Starch, Glycogen etc.
Fructosan: Inulin
Galactosan: Agar
2. Heterosaccharides: The Disaccharides usually contains an Acid sugar (D-
Glucuronic acid or its C5 epimer Iduronic acid) and an Amino sugar (the amino sugar may
be sulfated on non-acetylated Nitrogen). E.g. Hyaluronic acid.
We can also classify Polysaccharides by their work, like-
9. 1. Storage
Polysaccharides:
Starch [(C6H10O5)n] : -
Most common storage polysaccharide in plants
-Composed of 10 – 30% Amylose and 70-90% Amylopectin depending on the source
(a) Amylose is a linear polymer of α-D-glucose, linked together by α 1→4 glycosidic
linkages. It is soluble in water, reacts with iodine to give a blue color and the
molecular weight of Amylose ranges between 50, 000 – 200, 000.
(b) Amylopectin is a highly branched polymer, insoluble in water, reacts with iodine
to give a reddish violet color. The molecular weight ranges between 70, 000 - 1 000,
000. Branches are composed of 25-30 glucose units linked by α 1→4 glycosidic linkage
in the chain and by α 1→6 glycosidic linkage at the branch point.
10.
11. Suspensions of Amylose
in water adopt a helical
conformation
Iodine (I2) can insert in
the middle of the Amylose
helix to give a blue color
that is characteristic and Figure 3: Suspensions of
Amylose in water adopt a
helical conformation
diagnostic for starch
12. Starch can be hydrolysed into simpler carbohydrates by acids, various enzymes, or a combination of the
two. The resulting fragments are known as dextrin. The extent of conversion is typically quantified
by dextrose equivalent (DE), which is roughly the fraction of the glycosidic bonds in starch that have
been broken.
These starch sugars are by far the most common starch based food ingredient and are used as
sweetener in many drinks and foods. They include:
• Maltodextrin, a lightly hydrolysed (DE 10–20) starch product used as a bland-tasting filler and
thickener.
• Various glucose syrups (DE 30–70), also called corn syrups in the US, viscous solutions used as
sweeteners and thickeners in many kinds of processed foods.
• Dextrose (DE 100), commercial glucose, prepared by the complete hydrolysis of starch.
• High fructose syrup, made by treating dextrose solutions with the enzyme glucose isomerase, until
a substantial fraction of the glucose has been converted to fructose. In the United States sugar
prices are two to three times higher than in the rest of the world, which makes high fructose corn
syrup significantly cheaper, so that it is the principal sweetener used in processed foods and
beverages. Fructose also has better microbiological stability. One kind of high fructose corn syrup,
HFCS-55, is sweeter than sucrose because it is made with more fructose, while the sweetness of
HFCS-42 is on par with sucrose.
• Sugar alcohols, such as maltitol, erythritol, sorbitol, mannitol and hydrogenated starch hydrolyse,
are sweeteners made by reducing sugars.
Significance-
13. Glycogen [C24H42O21]:
-Also known as animal starch
-Stored in muscle and liver
-Present in cells as granules (high MW)
-Contains both α(1,4) links and α (1,6) branches at every 8 to 12 glucose unit
-Complete hydrolysis yields glucose
- With iodine gives a red-violet color
-Hydrolyzed by both α and β-amylases and by glycogen phosphorylase
Significance-
-In the liver, glycogen synthesis and degradation are regulated to maintain
blood-glucose levels as required to meet the needs of the organism as a whole.
Glycogen serves as a buffer to maintain blood glucose level.
-In contrast, in muscle, these processes are regulated to meet the energy needs
of the muscle itself.
- The concentration of glycogen is higher in the liver than in muscle (10% versus
2% by weight), but more glycogen is stored in skeletal muscle overall because of
its much greater mass.
15. Figure 5 Jerusalem artichokes
Inulin:
-b-(1,2) linked fructofuranoses
-Linear ,no branching
-Lower molecular weight than starch
-Colors yellow with iodine
-Hydrolysis yields fructose
-Sources include onions, garlic, dandelions and Jerusalem artichokes
-Used as diagnostic agent for the evaluation of glomerular filtration rate (renal function te
Significance-
-used clinically as a highly accurate measure of glomerular filtration rate (GFR)
-Used as a soluble dietary fiber
-Used as appetite suppressant
-Used as a low glycemic index sweetener
-Also used as a fat/cream substitute
16. 2. Structural Polysaccharides:
Cellulose [(C6H10O5)n]:
-Polymer of b-D-glucose linked by b(1,4) linkages
-Yields glucose upon complete hydrolysis
-Partial hydrolysis yields cellobiose
-Most abundant of all carbohydrates
-Gives no color with iodine
-Cellulose is tasteless, odorless and insoluble in water and
most organic solvents.
Significance—
Microcrystalline cellulose: used as binder- disintegrant in tablets
-Methyl cellulose: suspending agent and bulk laxative
-Oxidized cellulose: hemostat
-Sodium carboxymethyl cellulose: laxative
-Cellulose acetate: rayon; photographic film; plastics
-Cellulose acetate phthalate: enteric coating
-Nitro cellulose: explosives; collodion (pyroxylin)
18. Chitin:
-Chitin is the second most abundant carbohydrate polymer of N- Acetyl
Glucosamine
-present in the cell wall of fungi and in the exoskeletons of crustaceans, insects
and spiders
Figure 6 Structure of Chitin
-chitin is used commercially in coatings (extends the shelf life of fruits and meats.
19. Pectin :
Pectin is a family of complex polysaccharides that contain 1,4-linked α-D-galacto
syluronic acid residues. They are present in most primary cell walls and in the non-
woody parts of terrestrial plants. a
Significance
• Main use as gelling agent (jams, jellies)
dependent on degree of methylation
high methoxyl pectin gel through H-bonding and in presence of sugar and
acid
low methoxyl pectin gel in the presence of Ca2+ (‘egg-box’ model)
• Thickeners
• Water binders
• Stabilizers
Figure 8 Structure of Pectin
20. 3. Acidic Polysaccharides: Acidic polysaccharides are polysaccharides that
contain carboxyl groups, phosphate groups and/or sulphuric ester groups
Hyaluronic acid (D-glucuronate + GlcNAc)n-
Occurrence: synovial fluid, ECM of loose connective tissue. Serves as a lubricant
and shock absorber.
-Hyaluronic acid does not contain any sulfate and is not found covalently attached
to proteins.
-It forms non-covalently linked complexes with Proteoglycans in the ECM.
-Hyaluronic acid polymers are very large (100 - 10,000 kDa) and can displace a large
volume of water.
Figure 9 Structure of Hyaluronic Acid
21. Dermatan sulphate (L-Iduronate + GalNAc sulfate) n :
Occurrence: skin, blood vessels, heart valves
Chondroitin sulphate (D-glucuronate + GalNAc sulfate)n :
Occurrence: cartilage, tendons, ligaments, heart valves and aorta.
It is the most abundant GAG.
Figure 11 Dermatan SulfateFigure 10 Chondroitin
Sulfate
22. Pathogenic bacteria commonly produce a thick, mucous-like, layer of polysaccharide.
This "capsule" cloaks antigenic proteins on the bacterial surface that would otherwise
provoke an immune response and thereby lead to the destruction of the bacteria.
Capsular polysaccharides are water-soluble, commonly acidic, and have molecular
weights on the order of 100-2000 kDa.
3. Bacterial
Polysaccharides:
Dextran: -
Products of the reaction of glucose and the enzyme Transglucosidase from Leuconostoc
mesenteroides
-Contains α (1,4), α(1,6) and α (1,3) linkages
-MW: 40,000; 70,000; 75,000
-Used as plasma expanders (treatment of shock)
-also used as molecular sieves to separate proteins and other
large molecules (gel filtration chromatography)
23. Xanthan :
Source: Product of bacteria Xanthomonas campestris
Structure: cellulose-like backbone (b-1,4-poly-glucose) with trisaccharide
branches (stubs) on alternate monomers on the backbone carrying carboxylic
acid residue
Significance:
- Double helical conformation
- Pseudo plastic
- Shear-thinning
- Thickener
- Stabilizer
- Emulsifier
- Foaming agent
- Forms synergistic gels with galactomannans
- Water soluble, viscous, non-gelling. Viscosity is only slightly temperature dependent
25. SUMMARY
Homopolysaccharides are polymers of similar
monomer monosaccharides linked together by
Glycosidic linkages. Structurally they may be
Glucosan, Fructosan or Galactosan. Functionally
they may be storage, structural, acidic or bacterial
polysaccharides
Heteropolysaccharides are polymers of repeating
disaccharide units with enormous diversity. They
are components of ECM, joints, cartilages, tendons,
cornea and sclera. Heparin is an anticoagulant
