Glycosidic bonding

I.A.BHATTIRepresented By : IRSHAD ALI BHATTI

Carbohydrates are the richest bio-molecules on Earth. Carbohydrates are widely distributed in plants and animals; they have significant structural and metabolic roles.

Three Types of Carbohydrates occur.

1) Monosaccharides2) Disaccharides3) Polysaccharides

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Carbon, Hydrogen, and Oxygen are main components of Carbohydrates.

All three elements have definite ratio of

C, H,O.. 1:2:1

The Simplest Form of carbohydrates are Monosaccharides, which are glucose, galactose, and fructose.

Monosaccharides form Disaccharides and Polysaccharides like Lactose, Maltose, Sucrose, Starch, Glycogen, Cellulose.etc

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There are three monosaccharides involved in formation of Disaccharides 1) Glucose2) Fructose3) Galactose

Monosaccharides Combine Each Other To Form Disaccharide

Disaccharide: They give two same or different monosaccharides on hydrolysis with general formula of C12H22O11. Like; sucrose, maltose, lactose etc.

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Glycosides are compounds that yield one or more sugars upon hydrolysis.

The term glycoside is a generic term for natural product that is chemically bound to a sugar.

Among the sugars found in natural glycosides, D glucose is the most abundant one.

Cardiac glycosides are organic compounds containing a glycoside (sugar) that act on the contractile force of the cardiac muscle.

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the formation of a glycoside by the reaction of an aldose or ketose with an alcohol in the presence of an acid catalyst is known as glycosidation.

The formation of carbohydrates (Disaccharides, Polysaccharides)

is also an example of Glycosidation.

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Fischer glycosidation (or Fischer glycosylation) refers to the formation of a glycoside by the reaction of an aldose or ketose with an alcohol in the presence of an acid catalyst. The reaction is named after the German chemist, Emil Hermann Fischer, winner of the Nobel Prize in chemistry, 1902, who developed this method between 1893 and 1895

Hermann Emil Fischer

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Question Rise In All Minds…!!!!

What is the Backbone of formation of All Carbohydrates………????How …. ??

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The Glycosidic Bonds (Linkages)

This is formed via a condensation reaction and a “bridge” is created. This “bridge” is called a GLYCOSIDIC BOND.

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O-glycosidic bonds, in reference to the glycosidic oxygen that links the glycoside to the aglycone or reducing end sugar.

S-glycosidic bonds where the oxygen of the glycosidic bond is replaced with a sulfur atom.

N-glycosidic bonds, have the glycosidic bond oxygen replaced with nitrogen. Substances containing N-glycosidic bonds are also known as glycosylamines;

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Monosaccharides Joined By Glycosidic Covalent Bond

A carbon–oxygen bond is a covalent bond between carbon and oxygen and one of the most abundant in organic chemistry and biochemistry.

During polymerization, carbonyl group of one monosaccharide unit gets condenses with alcoholic unit of another monosaccharide to form disaccharide unit.

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First of all we have to change the Glycoside from chain form to Ring or Cyclic form

Example Of Formation Of D-Glucose

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In O-Glycosidic Bonding There are Two Types of Linkages

1) Alpha Linkage2) Beta Linkage

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Maltose is a disaccharide, formed by two glucose units. It occurs in cells as a breakdown product of starch. It is also formed in the seeds during germination. It is commonly called malt sugar.

The glycosidic bond of maltose is formed between the OH of carbon 1 and carbon 4 of 2 glucose monomers. Therefore it forms an alpha (1–> 4) glycosidic bond.

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Lactose is a disaccharide found in milk and hence commonly called milk sugar. It is formed by condensation of a glucose molecule and a galactose molecule.

composed of a glucose and a galactose monomer. They form a beta (1–> 4) glycosidic bond.

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Sucrose is disaccharide found extensively in plants. It is commonly called cane sugar. It is formed by a condensation of a molecule of glucose and a molecule of fructose.

Sucrose links the anomeric hydroxyls of glucose and fructose to form an alpha (1–>2) glycosidic bond.

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The most abundant natural polymer found in the world. Found in the cell wall of almost all plants, it provides physical structure and strength.

Cellulose is a straight chain polysaccharide with beta (1–>4) linkages.

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Amylose is a straight chain with alpha (1–>4) linkages

Amylopectin is an alpha (1–>4) chain with alpha (1–>6) .

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