1. CARBOHYDRATE COMPOUNDS
OLIGO-
AND POLYSACCHARIDES

2. Carbohydrates compounds in contrast of monosaccharaides are exposed to hydrolysis with formation of simpler carbohydrates

3. Carbohydrates compounds are subdivided on:
Oligosaccharides at which hydrolysis from two to ten molecules of monosaccharide's are formed;
Polysaccharides at which hydrolysis hundreds and thousands molecules are formed;
Homopolysaccharides, hydrolyzed with the monosaccharide's formation of one kind;
Heteropolysaccharides, which is hydrolyzed with the formation of various monosaccharide's.

4. Disaccharides
Among the oligosaccharides distinguish disaccharides, which are compound of two identical or of different monosaccharide's single unit.
Disaccharides - maltose, cellobiose, lactose exist in the nature as independent substances.

5. Disaccharides are formed from the monosaccharide's residues, connected by glycosidic bond.

6. In the formation of this bond participates two OH - groups, therefore it is possible to consider disaccharides as O- glycoside.

7. reducing disaccharides non-reducing disaccharides
for example
maltose
sucrose

8. Reducing disaccharides
Reducing disaccharides are concern: maltose, cellobiose and lactose. Of these in the formation of glycosidic bond participates: the first monosaccharide’s hemiacetal hydroxyl group of C1 and the second monosaccharide’s alcoholic hydroxyl group of C4. Thus in the disaccharide of the second monosaccharide hemiacetal OH - group remains free, that causes a presence of specific properties: cyclo-oxo- tautomerism, mutarotation, reducibility.

9. … cyclo-oxo- tautomerism

10. Maltose
Maltose - the basic product of the starch decomposition with the help of enzyme secreted by the salivary glands. Maltose is 3 times less sweet, than sugar; it is completely assimilated by a human organism.

11. Maltose consists from the a-D-glycopyranose and a (or B-)-D-glycopyranose, connected by a(1→4) glycosidic bond. It means that the first monosaccharide is always a-anomer.

12. Cellobiose
Cellobiose in the pure state meets is seldom in the nature. It is a fragment of cellulose and is formed by incomplete hydrolysis of this polysaccharide.

13. Cellobiose consists from the B-D-glucopyranose and a- (or B-)-D-glucopyranose, connected by B(l→4) glycosidic bond. It means that in difference from maltose in cellobiose the first monosaccharide - always B-anomer.

14. Lactose
Lactose - milk-sugar. It contains in milk of the mammal (4-6 %), in female milk - up to 8 %. Lactose in 4-5 times less sweet, than saccharine, therefore it is applied in a pharmaceutical industry at tablets manufacturing, powders and as a nutrient materials to sucking. However, lactose is not assimilated by some people because of insufficiency at them lactase enzyme. ! It should be taken into account in pediatrics, as children with lactase insufficiency cannot be reared with artificial lactic mixtures.

15. Lactose consists from the residues of B-D-galactopyranoses and a-(or B)-D-glucopyranoses, connected by B(l→4) glycosidic bond

16. From female milk it is extracted more than 10 oligosaccharides, where lactose is the structural component. Such oligosaccharides are great importance at the intestinal flora formation of newborns.
Some of them suppress the propagation of pathogenic intestinal bacteria. With their action relate curative properties of human milk. Besides oligosaccharides, containing the lactose connected with the sialic acid residue, are active against activators of tetanus and cholera.

17. Cyclo-oxo-tautomerism
Cyclo-oxo-tautomerism, i.e. ability of disaccharides to exist as an equilibrium mixture of the oxo and cyclic forms, is typical only for the reducing disaccharides. It is caused by presence of the free hemiacetal hydroxyl group in it. Because of it such disaccharides saves their ability to open a cycle with formation aldehyde groups. Aldehydic group in the particular requirements can be oxidized to carboxylic. Because it disaccharides exhibits reduction properties.

18. … cyclo-oxo- tautomerism

19. Mutarotation : interconversion of α- and β- anomers
Mutarotation is one more specific property of the reducing disaccharides. It is closely connected with cyclo-oxo-tautomerism.
Mutarotation it is a sample of material able to rotate the plane of polarization of a beam of transmitted plane-polarized (optical activity).

20. In a crystal state monosaccharide's and disaccharides exist, mainly, as a-anomers. At dissolvent, owing to cyclo-oxo-tautomerism, they transform to B-anomers. Therefore in a just prepared solution of saccharine eventually the value and a direction of a plane-polarized light wedged ray will vary. These changes are observed until approximately 60% of substance will not pass to more inconvertible B form. That is the phenomenon of disaccharides mutarotation.

21. Non-reducing disaccharide
Non-reducing disaccharide is sucrose.
It is most significant from the reduced disaccharides.
Saccharine contains in a sugar cane, sugar beet, juices of fruits and berries.
It is formed from the residues of a-D-glucopyranoses and B-D-fructofuranoses connected by a,B-(1→2)-glycosidic bond.
Such bond is carried out by the hemiacetal hydroxyls of both monosaccharide's

22. As saccharine does not contain free hemiacetal hydroxyl groups, it is not capable to cyclo-oxo-tautomerism.
Therefore sucrose does not show reduction properties and its solutions does not mutarotated.

23. Disaccharide, as well as others oligosaccharides, are easily hydrolyzed in the acid environment with rupturing of the glycosidic bonds.

25. Polysaccharides
Polysaccharides (glycan's) or polyoses are high-molecular products of monosaccharide's poly condensation, connected among themselves by glycosidic bonds. They can be considered as O-glycoside.
Essentially they do not differ from oligosaccharides with their structure, difference - only in amount of the monosaccharide's repeating units.

26. Every monosaccharide for the glycosidic bond formation with following single unit provides hemiacetal hydroxyl, and for bond with previous - alcoholic hydroxyl group.

27. In polysaccharides of a vegetative origin, basically, (1→4) and
In polysaccharides of an animal and bacterial origin - still in addition (1 → 2) and (1 → 3) - glycosidic bond.
In polysaccharides of a vegetative origin, basically, (1→4) and
(1 → 6) - glycosidic bond are realized.

28. At the end of a chain there is a residue of a reducing monosaccharide with the free hemiacetal group.
However, its quota concerning all macromolecule is not big, that’s why polysaccharides exhibit very weak reduction properties.

29. Polysaccharides have a high molecular weight (from 104 up to 109).
As well as for all high-molecular substances, more composite spatial organization of molecules is characterizing for them.
Therefore alongside with primary structure they also possess the secondary structure.

30. The primary structure is the particular sequence of the monosaccharide's residues in polysaccharide chains.
The secondary structure is an arrangement of a macromolecular chain of polysaccharide in space. Polysaccharide chains can be branched and unbranched (linear), helicoids.

31. Homopolysaccharides
For homopolysaccharides use the general name glycans. But in dependence on monosaccharide's structure which form them, distinguish: glucans, manna's, galactans, etc.
The general molecular formula of these compounds is (C6Hi0O5)n.

32. Homopolysaccharides of a vegetatic origin is starch, cellulose, pertinacious substances;
an animal - glycogen, chitin;
bacterial - dextrans.

33. Cellulose
Cellulose is the most widespread vegetative polysaccharide.

34. It is homopolysaccharide, as it is consist from the residues of only B-D-glucopyranoses, connected by B-(l→4)-glycosidic bonds

35. Starch
Starch is an associate of two homopolysaccharides: amylose (10- 20%) and amylopectin (90-80%) connected among themselves by hydrogen bonds and constructed from the residues of a-D-glucopyranose.
Starch is formed during photosynthesis in plants and reserved in tubers, roots and seeds. It contained in bread, potato, vegetables and is the important source of nourishment.
In medicine it is used for making powders, pastes, tablets.

36. Amylose is a glucose polymer with a(14) linkages.
The end of the polysaccharide with an anomeric C1 not involved in a glycosidic bond is called the reducing end.

37. Amylopectin is a glucose polymer with mainly a(14) linkages, but it also has branches formed by a(16) linkages. Branches are generally longer than shown above.
The branches produce a compact structure & provide multiple chain ends at which enzymatic cleavage can occur.

38. Glycogen
Glycogen, the glucose storage polymer in animals, is similar in structure to amylopectin.
But glycogen has more a(16) branches.
The highly branched structure permits rapid glucose release from glycogen stores, e.g., in muscle during exercise.
The ability to rapidly mobilize glucose is more essential to animals than to plants.

40. It contains in a liver (up to 20%), in muscles (~ 4%) and it carries out a function of the reserve carbohydrates. Because of the huge size its macromolecule does not pass through a membrane and remains inside a cell, till then the need in energy appears.

41. During the process of vital activity, when there is a need for glucose in a cell, as an energy source (the physical and mental strain, stressful states), occurs its ferment elimination from glycogen. It is carried out first of all on the ends of chains and accompanied with they energy allocation. In the course of the chain branching glycogen has a great amount of end- residues.

42. Heteropolysaccharides
Play the important role in animal organisms.
They consist from various monosaccharide units.

43. To them concern:
Heparin - natural anticoagulant prevent of blood coagulability. It contains in small amounts in a liver, blood, lung and spleen.
Chondroitin sulfates contain in a connecting tissue, skin, cartilages and tendons. They are esters of a sulfuric acid.
Hyaluronic acid contains in an umbilical cord, an articulate liquid, vitreous body of eyes. It carries out a function of intercellular lubricant, therefore it presents at tendons, skin, cartilages. Possessing of a high viscosity and stickiness provides impermeability of a connecting tissue for pathogenic bacteria. At the same time at the presence of hyaluronic acid elasticity of tissues increases.

44. Heparan sulfate is initially synthesized on a membrane-embedded core protein as a polymer of alternating N-acetylglucosamine and glucuronate residues.
Later, in segments of the polymer, glucuronate residues may be converted to the sulfated sugar iduronic acid, while N-acetylglucosamine residues may be deacetylated and/or sulfated.

45. Thank you for your attention