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Chemistry
and
Functions
of
Carbohydrates
SYNOPSIS
Introduction
Definition of Carbohydrates
Classification of Carbohydrates
Study of Biomedically Important
Carbohydrates:
Monosaccharides
Disaccharides
Polysaccharides
Mucoproteins and Glycoproteins.
Biomedical Importance of Carbohydrates.
Introduction
What are Carbohydrates?
Carbohydrates are organic
biomolecules abundantly present in
the nature.
Found in the cells of plants and
animals.
The term "Carbohydrate" was coined
by "Karl Schmidt".
Carbohydrates Biosynthesis
Carbohydrates are predominantly
biosynthesized by plants through
photosynthesis.
Glucose is synthesized in plants
from CO2, H2O, and solar energy
from the sun.
Photosynthesis
chlorophyll
6 CO2 + 6 H2O
C6H12O6 + 6 O2
Sunlight Glucose
(Simple Carbohydrate)
(+)-Glucose Starch or Cellulose
(Complex Carbohydrates Of Plants)
Animals and Human beings
cannot biosynthesize
Carbohydrates
predominantly.
To fulfill metabolic and
structural role in human
beings,
It is essential to ingest
carbohydrates through
food substances of plant and
animal origin.
Thus Carbohydrates are chief
constituents of human food.
R.D.A for Dietary Carbohydrates=
400-600 gm/day.
However in a critical
condition when cells are
deprived of Glucose
Human body biosynthesizes
Glucose using the non
carbohydrate precursors
present in body via
Gluconeogenesis.
Functions of Carbohydrates
Carbohydrates serve as
primary source of
energy/Fuel of body
( Metabolic role).
Carbohydrate (Glucose)
is oxidized in living cells
of human body to
produce CO2, H2O, and
energy(ATP).
Carbohydrates provide
skeletal framework to cells
,tissues, and organs of
body.(Structural role)
Carbohydrates are associated
to many other roles with
human beings.
DEFINITION OF
CARBOHYDRATES
Old Definition of Carbohydrates
Empirical formula/General formula for
simple carbohydrates : Cn (H2O)n
Where n = number of carbon atom
present in carbohydrate structure.
Old Definition-
Carbohydrates are "Hydrates of
Carbon"
Old definition is not valid since-
Certain Carbohydrates ?
Rhamnose did not fit in the
empirical formula of carbohydrates.
Certain non Carbohydrates ?
Lactate and Acetate fitted in the
empirical formulae.
Observe the following
chemical structures of
simple Carbohydrates:
Glucose and Fructose
Aldose
Ketose
(e.g., Glucose) have
(e.g., Fructose) have
an aldehyde group at a ketone group,
one end.
usually at C2.
Simple Carbohydrates has many
Hydroxyl groups (Polyhydroxy).
Simple Carbohydrates has carbonyl/
functional groups as Aldehyde or
Ketone.
Simple Carbohydrates(Glucose/Fructose)
repeatedly linked to form its condensed
complex carbohydrates for ex Starch,
Inulin.
The hydroxyl groups may be free
or substituted by any other
groups.
Simple Carbohydrates on
chemical reactions produces
derivatives of Carbohydrates.
New Definition of Carbohydrates
Carbohydrates are organic
biomolecules, abundantly
present in the plant and animal
bodies, chemically composed of
Polyhydroxy Aldehyde or
Polyhydroxy Ketone, their
condensed products or their
derivatives.
Classification Of Carbohydrates
Depending Upon Number of Saccharide Units
Four Main Classes of Carbohydrates
Monosaccharides
(1 Saccharide Unit)
Disaccharides
(2 Saccharide Units)
Oligosaccharides
( 3-10 Saccharide Units)
Polysaccharides
( More than 10 Saccharide Units)
Monosaccharides Sub Classification
Monosaccharides are sub
classified on the basis of:
Functional Group
Number of Carbon atoms.
Number of
Aldoses
Ketoses
Carbon Atoms
(Aldehyde-CHO)
(Ketone -C=O)
3
Aldo Triose
Keto Triose
Triose
Glyceraldehyde
Di HydroxyAcetone
4
Aldo Tetrose
Keto Tetrulose
Tetrose
Erythrose
Erythrulose
5
Aldo Pentose
Keto Pentulose
Pentose
Ribose, Xylose, Arabinose
Ribulose, Xylulose
6
Aldo Hexose
Keto Hexose
Hexose
Glucose, Galactose ,Mannose
Fructose
7
Aldo Heptose
Keto Heptulose
Heptose
SedoHeptose
SedoHeptulose
Disaccharides
Disaccharides has 2
Monosaccharide units
linked by glycosidic bond.
Disaccharides may be
reducing or non reducing
Type Of Disaccharides
Reducing Disaccharides ?
Lactose (Glu-Gal)
Maltose (Glu-Glu)
Non reducing Disaccharides-
Sucrose(Glu-Fru)
Oligosaccharides Sub Classification
Oligosaccharides has 3-10
Monosaccharide units linked
by glycosidic bonds.
Oligosaccharides are sub
classified on the basis of
number of Saccharide units.
Number of
Type Of Oligosaccharides
Monosaccharide
(3-10 Monosaccharide Units )
Units
3
Trisaccharides
Maltotriose (Glu-Glu-Glu)
Raffinose (Glu-Fru-Gal)
4
Tetrasaccharides
Stachyose (Glu-Fru-2Gal)
5
Pentasaccharides
Verbascose (Glu-Fru-3Gal)
Polysaccharide Sub Classification
Polysaccharides/ Glycans
contain more than 10, same/
different Monosaccharide
units linked by glycosidic
linkages.
Types of Polysaccharides
Homopolysaccharides/
Homoglycans-
Contains more than 10 same repeating
units.
Heteropolysaccharides /
Heteroglycans-
Contains more than 10, different
repeating units.
POLYSACCHARIDES/ Glycans
( More than 10 Monosaccharide Units )
Homopolysaccharides/ Homoglycans
( > 10 Same Repeating Units )
Glucosans
Fructosans
(Repeating Unit of Glucose/Polymer (Repeating Unit of
of Glucose)
Fructose/Polymer of
Starch
Fructose)
Glycogen
Cellulose
Inulin
Dextrin
Dextran
Hetero Polysaccharides
( More than 10 Different
Repeating Units )
Animal
Heteropolysacchrides
Mucopolysaccharides (MPS)
OR
Glycosaminoglycans (GAGs)
Types And Examples of
Mucopolysaccharides
Acidic Non Sulfated MPS:
Hyaluronic Acid
Acidic Sulfated MPS:
Heparin
Heparan Sulfate
Chondritin Sulfate
Dermatan Sulfate
Keratan Sulfate
Neutral MPS:
Blood Group Substances
Plant Heteropolysaccharides
Agar
Pectin
Lignin
Gum
What are Sugars?
Sugars are chemically simple
Carbohydrates Monosaccharides and
Disaccharides.
Sugars are Crystalline Solid substances.
Soluble in water
Sweet in taste
Structure possess asymmetric /chiral
carbon atoms/stereogenic centers.
The carbonyl/
functional groups of
Carbohydrates may be
present as free or
bound (involved in
glycosidic bonds).
Types Of Sugars
Reducing Sugars
Non Reducing
Sugars
Reducing Sugar
Sugar structure possessing free or
potential(reactive) aldehyde or
ketone group is termed as
reducing sugar.
Reducing sugars show reducing
property efficiently in alkaline
medium and reduces certain
metallic ions as- Cu++;Bi++;Fe+++
Reducing Sugars answer following
tests positive
Benedict's Test
Fehling's test
Nylander's Test
Form Osazones.
Reducing Shows Mutarotation
(Change in Optical activity)
Examples Of Reducing Sugars
All Monosaccharides are reducing sugars.
Monosaccharides are strong reducing
agents.
Monosaccharides?
Ribose, Glucose, Galactose, Fructose.
Disaccharides are weak reducing agents.
Reducing Disaccharides-
Lactose, Maltose.
Non Reducing Sugars
Sugar structure not possessing
free or potential aldehyde or
ketone group in its structure is
termed as non reducing sugar.
Non reducing sugar does not
show reducing property and do
not reduce metallic ions.
Non reducing sugars give following
reducing tests negative.
Benedict's Test
Fehling's test
Nylander's Test
Do not form Osazones
Non Reducing sugars do not exhibit
Mutarotation (Change in Optical activity)
Examples of Non reducing Sugars
Non reducing Disaccharides.
Sucrose (Biomedically Important)
Trehalose (Glu-Glu linked with
(1-1) glycosidic bond)
Polysaccharides/Complex
Carbohydrates are Non reducing.
Sugar/Sugar Derivatives
Percent
Sweetness
Glucose
75
Fructose
175
(Sweetest Sugar)
(Highest)
Galactose
30
Sucrose
100
Lactose
20
Maltose
30
Xylitol
250
Non Carbohydrate Percent Sweetness
Synthetic Sweetners
Saccharin
45,000 times
Aspartame
18,000 times
(Asp-Phe)
Thaumatin and
10,000 times
Monellin
Cyclamate
1000 times
Biomedical Importance of Sugars
Sugars are sweetening
agents used in
preparations of fruit
juices, sweet recipes
which gives delicious taste.
Sugars have dietary and
calorific value.
Ingested sugars are digested
,absorbed and assimilated to
produce chemical form of
energy ?ATP, which is further
used for body activities.
Carbohydrates are
Optically Active and
Show Stereoisomerism
All Carbohydrates except Di Hydroxy
Acetone(DHA) possess asymmetric
carbon atoms in their structure.
Presence of Asymmetric carbon atoms
confer two properties:
Optical Activity
Stereoisomerism.
Optical Activity
Optically active solutions when
placed in the tube of Polarimeter.
If moves the plane of polarized
light toward right are dextro
rotatory (d/+).
If moves the plane of polarized
light toward left are laevo rotatory
(l/-).
Stereoisomerism
Stereoisomerism is
due to presence of
chiral carbon
atoms/stereogenic
centers.
Stereoisomers are type of
isomers
Which have same chemical and
molecular formula,
The structure slightly differs in
the spatial orientation of
groups around the carbon atom.
Biomedically Important
Monosaccharides
Monosaccharides (Simple Sugars)
Monosaccharides are simplest class
of Carbohydrates.
They are composed of one
saccharide unit.
Monosaccharides cannot be further
hydrolyzed.
Monosaccharides are building
blocks/monomeric units of higher
forms of Carbohydrates.
Glyceraldehyde/Glycerose
Simplest Carbohydrate
(Reference sugar)
Glyceraldehyde is
a Monosaccharide
Chemically ?
Aldo Triose
C3H6O3
Occurrence/Sources of Glyceraldehyde
In Cytoplasm of cells
Biomedical Importance's
Glyceraldehyde -3-Phosphate
is an intermediate of
Glycolysis and HMP shunt.
Glyceraldehyde is reduced
to Glycerol which is used
during Lipid and Glucose
biosynthesis.
DihydroxyAcetone
It is a Monosaccharide
DHA is a Functional
Isomer of Glyceraldehyde.
Chemistry Of DHA
Dihydroxy Acetone is a
Keto Triose.
C3H6O3
DHA has no chiral atom
in its structure.
Occurrence/Sources Of DHA
In Cytoplasm of Cells
Biomedical Importance's Of DHA
Dihydroxy Acetone
Phosphate(DHAP) is an
intermediate of Glycolysis.
DHAP is readily
interconvertable to
Glyceraldehyde -3-PO4.
Erythrose
Chemistry :
Erythrose is a Monosaccharide
Erythrose is an Aldo Tetrose
C4(H2O)4
Occurrence/Sources :
In Cytosol of cells
Biomedical Importances :
Erythrose -4-Phosphate is an
intermediate of HMP shunt.
Ribose
Chemistry :
Ribose is a Monosaccharide.
Ribose is an Aldo Pentose
C5(H2O)5
Occurrence/Sources :
In cells
Biomedical Importances of Ribose :
Ribose is an important component of
Ribonucleotides which forms RNA.
Ribose is component of certain Nucleotide
Coenzymes-
ATP, NAD+, NADP+,FAD
Deoxyribose
Deoxyribose is a
Monosaccharide
Derived from Ribose/
Derivative of Ribose
Chemistry :
Deoxyribose is a Aldo Pentose
Deoxyribose has one Oxygen atom
less than Ribose at C2.
Deoxyribose has no ?OH group at
C2
Instead has ?H at C2.
Occurrence/Sources :
In cells
Biomedical Importances Of
Deoxyribose :
Deoxyribose is a component of
Deoxyribonucleotides which
forms DNA.
Arabinose
Arabinose is a
Monosaccharide
Chemistry :
Arabinose is a Aldo Pentose
C5(H2O)5
Occurrence/Sources:
Gum Arabic and Cherries.
Biomedical Importances
Arabinose is a component
of Glycoproteins.
Xylose
Xylose is a Monosaccharide
Chemistry :
Xylose is an Aldo Pentose
C5(H2O)5
Occurrence/ Sources :
Wood Gum
Biomedical Importances :
Xylose is a component of
Glycoproteins and Proteoglycans
Xylulose
Xylulose is a
Monosaccharide
Chemistry :
Xylulose is a Keto Pentose
C5(H2O)5
Occurrence/ Sources :
In Cells
Biomedical Importances of Xylulose:
Xylulose -5-Phosphate is an
intermediate of HMP Shunt.
Xylitol reduced compound of Xylulose
is used as sweetener (250% Sweetness).
Ribulose
Chemistry:
Ribulose is a
Monosaccharide
Ribulose is a Keto
Pentose
C5(H2O)5
Occurrence/ Sources :
In Cytosol of cells.
Biomedical Importances
of Ribulose:
Ribulose-5-Phosphate occurs
as an intermediate of HMP
Shunt.
Glucose
Grape sugar
Chief blood sugar
Main sugar of body cells.
Also termed as Dextrose
Chemistry of Glucose
Glucose Chemically ?
Aldo Hexose.
Molecular Formula-
C6H12O6
C1 is an Anomeric
carbon of Glucose.
C1 has
carbonyl/Functional
group.
Structures Of Glucose
Cyclic forms for sugars
Fischer projections for a D Glucose
7P1-95
Fischer's and Haworth's Projection
Fischer's Projection
Cyclization of Glucose to hemiacetal is
spontaneous to form stable ring structures.
Haworth's Projection
Gluco Furanose -5 membered ring with Oxygen
atom in it.
Gluco Pyranose -6 membered ring with Oxygen
atom in it.
Monosaccharides can cyclize to
form Pyranose / Furanose forms
b =64%
a = 36%
Chair Conformation Of Glucose
Blood Glucose is more
thermodynamically stable in
D Glucopyranose form.
Occurrence/Sources of Glucose
Glucose is found in free or bound
state in nature.
Glucose is a component of
Disaccharides and Polysaccharides.
Glucose found-In fruits, human
blood and body cells.
Physical properties of Glucose
Glucose possess asymmetric/chiral
carbon atoms in its structure, this
confers 2 physical properties:
Optical Activity
Stereoisomerism
Optical Activity of Glucose
Optical activity for an aqueous
solution of Glucose is
dextrorotatory(+/d)
It rotates the plane of plain
polarized light in Polarimeter
towards right.
Hence Glucose is also termed
as Dextrose.
Specific rotation of Glucose
optical activity:
Pure -D Glucose = specific rotation
+112.2 ?
Pure -D Glucose = specific rotation
+18.7 ?
Isomers of Glucose
Cyclic structure of Glucose posses 5
asymmetric carbon atoms.
The number of isomers is 2n, where n is
the number of asymmetric centers.
According to Vant Hoff rule 25
Glucose posses 32 possible Isomers.
Functional / Structural Isomers of
Glucose
Glucose (Aldo Hexose) and
Fructose (Keto Hexose) .
These are Functional Isomers
their structure differs only at
functional groups.
Stereoisomer's Of Glucose
Stereoisomers are type of
isomers which have same
molecular formula; structure
differs only in the orientation
of groups in space.
Glucose Stereoisomers
D and L Glucose
Anomers
Epimers
D and L Glucose
Enantiomers/ Mirror images
of each other/Left and Right
Hand
Non superimposible/Non
overlapping.
To identify D and L Glucose
Look at the penultimate carbon atom
of Glucose (C5) /Farthest assymetric
carbon atom from carbonyl carbon
atom.
In D Glucose -OH is at R.H.S.
In L Glucose -OH is at L.H.S.
Enantiomers
Physical and chemical
properties of Enantiomers are
same, except optical rotation.
Sugars present in human
body are of `D' series.
Enzyme Racemase
interconvert `D'
and `L' isomers.
Anomers
-Glucose and -Glucose.
Anomers has group variations
at C1 Anomeric carbon atom of
Glucose .
In Fischer's projection at C1
-Glucose has -OH group at
R.H.S
In Fischer's projection at C1
-Glucose has ?OH group at
L.H.S.
Glucose anomers of
Haworth's projection shows
as follows.
-Glucose has -OH group
below the plane.
-Glucose has OH group
above the plane.
In the body
physiologically the most
thermodynamically
stable form of Glucose
is D Glucopyranose .
Anomerism
Glucose anomers are not stable
and tend to interconvert
constantly by opening and
reclosure of ring.
Anomerism is interconversion of
one form of anomer to another.
Anomerism exhibit Mutarotaion.
Epimers
Epimers are stereoisomers which
has variation in the orientation of
groups at C 2/ C3 / C4 of Glucose.
Epimers of Glucose
Galactose (C4 Epimer)
Mannose (C2 Epimer)
Mannose
Galactose
(C2 Epimer)
(C4 Epimer)
When Mannose and Galactose
structures are compared there
is variation at two different
carbon atoms (C2 and C4).
Mannose and Galactose are
not Epimers but they are
"Diastereoisomers".
Mutarotation
Mutarotation is
change in specific
rotation of an optically
active substance.
Criteria for an optically
active substance to exhibit
Mutarotaion:
Anomerism:
In aqueous solution the optically
active substance should exist in two
or more stereoisomeric forms by
ready interconversions.
Glucose Exhibits Mutarotation
Glucose in aqueous solution shows
`Anomerism'.
Glucose in aqueous solution
readily interconvert from
Glucose to Glucose and attain
an equilibrium mixture to exhibit
mutarotation.
Mutarotation is a physico chemical
property
Shown by certain optically active
substances ,who in aqueous solution has
capacity to interconvert from one
stereoisomeric form to other and attain
a constant equilibrium mixture,
This changes an initial specific rotation
to a constant specific rotation with the
passage of time.
Chemical Properties
OR
Chemical Reactions
OR
Derivatives Of Glucose
Reduction Reaction Of Sugars
Reduction Reaction
Glucose Sorbitol
(Sugar) (Sugar Alcohol)
During reduction reaction
the C1 carbonyl group
(-CHO) is reduced to primary
alcohol group (-CH2OH).
Sorbitol is
Polyol/Polyhydroxy Alcohol.
Sugar Alcohols taken in food are
of less calorific value.
They yield half energy in
comparison to sugars.
They are poorly absorbed.
Sugar alcohols if ingested reduces
weight.
They are prescribed for Diabetics.
Abnormal levels of Sorbitol found
in Diabetics, leads to Cataract
Excess Blood Glucose in
Diabetics, get reduced to
Sorbitol which further
deposits in the lens of eye
and forms Cataract.
Oxidation Reaction Of Sugar
Gluconic Acid
(Aldonic Acid)
(-CHO to -COOH)
Oxidation Reaction
Glucose
Glucuronic Acid
(Uronic Acid)
(-CH2OH to -COOH)
Glucosaccharic Acid
(Dibasic Aldaric Acid)
(-CHO &-CH2OH to ?COOH)
Aldehyde oxid'n
aldonic
acid
Terminal CH2OH
oxid'n Uronic acid
Aldehyde + Terminal CH2OH oxid'n
Aldaric acid/Saccharic acid
Uronic Acid of Glucose
Glucoronic acid is component
of Mucopolysaccharides.
Glucuronic acid serve as
conjugating agent in
detoxification reactions.
N-Glucosamine
N Acetyl Glucosamine
N Acetyl Galactosamine
Are Important constituents
of Mucopolysaccharides,
Glycoproteins and
Glycolipids
Glucose
Esteification
Glucose -6-Phosphate
Phosphorylation Reaction (Robinson Ester)
OR
Glucose-1-Phosphtae
(Cori Ester)
Reducing Property Of Glucose
Reducing property of
Glucose is Enolization/
Tautomerization reaction.
Glucose show efficient
reducing property in
alkaline medium .
Glucose in alkaline
medium forms Enediol
Enediol is a strong
reducing agent which
reduces cupric ions to
cuprous ions.
Glucose give positive test results
for following reducing tests:
Benedicts Test
Barfoeds Test
Fehlings Test
Nylanders Test.
Benedicts Test-Reduction of Cupric
ions in mild alkaline medium.
Barfoeds Test-Reduction of Cupric
ions in weak acidic medium.
Fehlings Test- Reduction of Cupric
ions in strong alkaline medium.
Nylanders Test-Reduction of
Bismuth ions in strong alkaline
medium.
Glycosides
Glycosides are derivatives of sugar.
Glycosides has Aglycone moiety linked to
C1 (anomeric carbon atom) of sugar by an
acetal linkage.
Sugar Acetal Linkage
Aglycone
Moiety
Aglycone moieties-
(Non Sugar, Hydroxyl group
containing compounds)
?Methanol
?Sterol
?Phenol
?Glycerol
Types of Glycosides-
Glucoside
(Contains Sugar as Glucose)
Galactoside
(Contains sugar as Galactose)
Occurrence and Uses of
Glycosides
Glycosides are naturally
occurring substances
present in plants and
animal bodies; which are
extracted and used as
drugs.
Glycosides
Examples and Therapeutic Use
S.No
Examples of
Therapeutic Use
Glycosides
1
Cardiac Glycosides
In treatment of cardiac
Digoxin /Digitonin
insufficiency.
Ovabain
2
Phlorizin
In treatment of Diabetes
(Glucose Transporter Inhibitor) mellitus.
3
Streptomycin
Antibiotic used to treat
bacterial infections.
4
Glucovanillin
Flavoring agent in Ice
creams and Puddings.
Biomedical Importance of Glucose
Glucose is a reduced compound and
has bond energy in its structure.
Glucose in body cells
Oxidized/Catabolized to liberate
chemical form of energy-ATP.
1 Glucose molecule on complete
oxidation produces 32 ATPs.
Glucose serve as primary source of
energy to all body cells.
Glucose is an universal fuel of fetus.
Brain, Erythrocytes ,lens cells, spinal
cord, peripheral nerves are completely
dependent on Glucose for its energy.
After well fed condition the free and
excess body Glucose is transformed to
Reservoir /Storage forms of Glucose
? Starch (In Plants)
? Glycogen (In animals)
Glucose still in excess is transformed to
Fat (TAG) and stored as depot fat.
(Unlimited).
Glucose is used for biosynthesis
of:
Glucuronic acid
Glucosamine
N-Acetyl Glucosamine
Galactose
Non essential amino acids
Glycosides
Galactose
Chemistry of Galactose
Galactose is a Monosaccharide
Aldo Hexose
C4 Epimer of Glucose
Occurrence/Sources
Galactose is never found free
It is a component of :
Milk Sugar Lactose
Mucopolysaccharides
Glycolipids and Glycoproteins.
Galactose on reduction form
Dulcitol.
Galactose on strong oxidation
forms Mucic acid.
(Galactosaccharic acid).
Galactose is abnormally elevated
in blood and excreted in urine ?
GALACTOSEMIA.
Biomedical Importance
Galactose has dietary and
calorific value.
Galactose is transformed to
Glucose in Liver and metabolized.
Galactose is used in biosynthesis of
Mucopolysaccharides,
Glycoproteins, Glycolipids.
Galactose along with Glucose forms
Lactose in lactating mothers .
Galactose is part of
nerve and brain
biochemicals, so
milk is essential to
infants.
Mannose
Mannose is a Monosaccharide
Chemically -Aldo Hexose
C2 Epimer of Glucose
Occurrence/Sources of Mannose
In Plants
Mannan (Polymer of Mannose)
Biomedical Importance Of
Mannose
Mannose component of
Glycoproteins.
Mannitol reduced compound of
Mannose is used as Diuretic to
treat Acute Renal failure.
Fructose
Fructose is a
Monosaccharide
Fructose is Sweetest Sugar.
Laevulose (Laevorotatory)
Chemistry Of Fructose
Fructose is a Keto Hexose
C6H12O6
C2 is anomeric carbon of
Fructose
Occurrence/Sources Of Fructose
In Fruits, Honey
Body cells, Semen.
Fructose is component
of Sucrose.
Fructose is more stable in
D Fructofuranose form.
Selivanoff `s test is characteristic
test for Fructose.
(positive result-Cherry red
color).
Fructose on reduction forms
Sorbitol and Mannitol.
Fructose-6-PO4 (Neubergs Ester )
Fructose-1,6- Bis Phosphate
(Harden Young Ester).
Abnormal excretion of Fructose in
urine is noted in persons suffering
from Essential Fructosuria.
Biomedical Importance Of
Fructose
Fructose has dietary and calorific
value.
In Liver Fructose is transformed to
Glucose and metabolized.
Fructose present in semen serves as
nutrient for Sperms.
Biomedically Important
Disaccharides
Disaccharides are class of
Carbohydrates, chemically
composed of two, same or
different Monosaccharide
units, linked by glycosidic
bond.
General Formula of
Disaccharides
Cn(H2O)n-1
Glycosidic Bonds
Glycosidic bonds are
Acetal/ Ketal bonds
involving the anomeric
carbon of Monosaccharides.
The Aldehyde/Ketone groups
participate in glycosidic bond,
Its involvement looses reducing
property since, they wont remain
free.
Glycosidic bonds are formed
with the interaction of two
hydroxyl groups of adjacent
sugar
residues(Monosaccharide)
with an elimination of water
molecule.
Glycosidic
Linkage
Glycosidic bonds are
covalent, strong bonds
,linking one Monosaccharide
to another.
Glycosidic bonds are formed
with / configuration.
Different glycosidic bonds
form a different molecule
with different properties.
Types of Glycosidic bonds:
? ( 1-4)
? (1-6)
? 1-2
? (1-1)
? (1-4)
Reducing end- End with free
anomeric carbon, not involved
in formation of glycosidic bond.
Non reducing end- End with
no free anomeric carbon, since
involved in formation of
Glycosidic bond.
Types of Disaccharides
Reducing Disaccharides
Lactose (Milk Sugar)
Maltose
(Malt Sugar, Product of Starch digestion))
Isomaltose (product of Starch digestion)
Lactulose (Laxative)
Cellobiose ( Product of Cellulose)
Non Reducing Disaccharides
Sucrose (Cane Sugar )
Trehalose
Lactose
(Milk Sugar)
Components and Linkage
of Lactose
Lactose is a Reducing Disaccharide
(1-4 ) glycosidic bond
D Galactose
D Glucose
Source / Occurrence Of Lactose
Milk and Milk products.
Lactating Mothers body.
Biomedical Importance Of Lactose
Lactose has dietary and calorific
value.
GIT enzyme Lactase digests
Lactose by cleaving (1-4)
glycosidic bond and releases free
Galactose and Glucose.
Lactase deficiency in GIT leads
to suffer from Lactose
Intolerance.
Certain bacteria can ferment
lactose to lactic acid - souring of
milk
(Lactobacillus).
Lactose may occur in urine during
trimester of pregnancy.
Maltose
Maltose is a reducing
Disaccharide
Malt Sugar
Components and Linkage Of
Maltose
D Glucose - D Glucose
(1-4 ) glycosidic bond
Glucose to form Maltose
+
Condensation
Hydrolysis
H2O
Source / Occurrence Of Maltose
Malt grain, Germinating seeds,
Maltova.
In human GIT, source of Maltose
is through Starch and Glycogen
digestion by Amylase
activity.
Maltose is obtained in
GIT as an end product of
Starch and Glycogen
digestion.
Biomedical Importance Of
Maltose
Maltose has dietary and
calorific value.
GIT enzyme Maltase digests
Maltose by cleaving (1-4)
glycosidic bond and releases
two Glucose units.
Isomaltose
Isomaltose is a reducing
Disaccharide.
Isomaltose is a product
of Starch and Glycogen
digestion.
Components and Linkage Of
Isomaltose
D Glucose - D Glucose
(1-6 ) glycosidic bond
Source /Occurrence Of Isomaltose
In human GIT
Isomaltose is obtained
from Starch and
Glycogen digestion
by -Amylase activity.
Biomedical Importance of
Isomaltose
Isomaltose has dietary and
calorific value.
Isomaltose is digested by GIT
enzyme Isomaltase to release
two Glucose units by cleaving
(1-6 ) glycosidic bond.
Cellobiose
Cellobiose is a reducing
Disaccharide.
Disaccharide obtained from
Cellulose Digestion.
Components and Linkage Of
Cellobiose
D Glucose - D Glucose
(1-4 ) glycosidic bond
Source / Occurrence of Cellobiose
Cellobiose obtained from
Cellulose digestion In GIT of
ruminants ( Cattle) .
Cellobiose is absent in
human GIT, since enzyme
Cellulase is absent which do
not digest Cellulose.
Biomedical Importance of
Cellobiose
Cellobiose is absent in
human beings.
Not of biomedical
Importance.
Lactulose
Lactulose is a
Reducing
Disaccharide
Type, Components and
Linkage of Lactulose
D Galactose - D Fructose
(1-4 ) glycosidic bond
Source / Occurrence Of Lactulose
In Plants
Lactulose:
Prepared by
alkaline
rearrangement of
lactose
Biomedical Importance Of
Lactulose
Lactulose has therapeutic
value; act as osmolar
laxative.
Relieves Chronic
Constipation.
Oral administration of
Lactulose relieves hyper
Ammonaemia in patients of
Hepatic Encephalopathy.
Treatment of Systemic
Encephalopathy By Lactulose.
Mechanism of action:
Lactulose is not digestible.
Bacterial flora convert it to Lactic and
Acetic acids that irritate the intestinal
wall.
Increases acidity of intestine ,this
moves ammonia from blood to the
intestine for neutralization.
Relieves Hyperammonaemia.
Sucrose
Sucrose is a Non Reducing Disaccharide
Cane sugar/ Common Table Sugar /Beet sugar
Components and Linkage Of
Sucrose
D Glucose- D Fructose
1- 2 glycosidic bond.
Why Sucrose is Non reducing?
Glucose (C1) and Fructose(C2)
anomeric carbon atoms are
involved in formation of
Glycosidic bond.
No free anomeric carbon
atoms.
Hence Non reducing.
Sucrose has no
free aldehyde
/ketone group
hence non
reducing
Sucrose is
dextrorotatory (d/+)
with specific rotation
+66.50.
Source /Occurrence Of Sucrose
In Plants ? Sugar cane,
Beet root.
Commercially prepared
from sugar cane.
Invert Sugar
Invert sugar is a product
of Sucrose hydrolysis.
Invert Sugar is a product
of Inversion Process.
Invert Sugar is a
hydrolytic mixture of
free Glucose and
Fructose obtained from
Sucrose hydrolysis.
Inversion process
A non reducing and
dextrorotatory Sucrose, on acid
hydrolysis/by action of enzyme
Invertase ,
Produces a hydrolytic mixture of
free, Glucose(+52.50) and
Fructose(-930) which is reducing
and laevorotatory(- 20.40).
Invert Sugar is Reducing.
Invert sugar is laevorotatory.
(since Fructose has high magnitude of optical
rotation -930)
Invert Sugar is sweeter than Sucrose
(since it contains free Fructose,a sweetest
sugar)
Uses Of Invert Sugar
Sweetening agent as it
is more sweet than
Sucrose.
Used in adulteration of
Honey.
Biomedical Importance Of Sucrose
Sucrose has dietary and calorific
value.
Sucrase or Invertase enzyme of
GIT cleaves 1- 2 Glycosidic
bond of Sucrose and release free
Glucose and Fructose ? i.e. Invert
Sugar.
Biomedically Important
Oligosaccharides
Oligosaccharides are
composed of 3-10
Monosaccharide units linked
by glycosidic bonds.
Oligosaccharide may be
branched or unbranched
chain.
Dietary Oligosaccharides are
not digested by human hence
has no calorific value.
Oligosaccharides are
components of Glycoproteins.
Biomedically Important
Polysaccharides/Glycans
Polysaccharides are complex
class of Carbohydrates,
Chemically composed of more
than ten, same or different
Monosaccharide units or their
derivatives
Repeatedly linked by glycosidic
linkages.
General
Formula of
Polysaccharides
(C6H10O5 )n
Iodine test is a
characteristic
test for
Polysaccharides
Iodine test is based on Physical
property of adsorption.
Iodine get adsorbed on complex
structure of Polysaccharides to
give characteristic color.
Homopolysaccharides
Homopolysaccharides are type
of Polysaccharides composed of
more than 10, same type of
Monosaccharide units
repeatedly linked by glycosidic
bonds.
Glucosan
Type of Homopolysaccharide
Repeating unit,of Glucosan is
Glucose
Glucosan is a Polymer of
Glucose.
Examples Of Glucosans
Starch
Glycogen
Cellulose
Dextrin
Dextran
Fructosan
Type of
Homopolysaccharide
Repeating unit in
Fructosan is Fructose.
Fructosan is a Polymer of
Fructose.
Example Of Fructosan
Inulin
Starch
Plant Homopolysaccharide
Chemistry Of Starch
Starch is Glucosan
Repeating Unit -
D Glucose (approx 7000)
Components of Starch-
Amylose and Amylopectin
Amylose
Amylose is 15-20%
Linear structure
D Glucose linked by
(1-4) glycosidic bond.
Amylopectin
Amylopectin is 80-85 %
Branched structure
Branching point appears after every
25-30 Glucose units.
It has (1-6) glycosidic bond at branching
point.
(1-4) glycosidic bonds in linear structure.
Starch is white ,odourless, tasteless
powder .
Starch is insoluble in cold water, but get
solubilized on heating and form gel
/paste.
Starch is a non reducing Carbohydrate.
Starch -Negative Benedicts Test.
Starch on Iodine reaction gives blue
color.
Source/Occurrence Of Starch
Plants- Seeds, Tubers, Roots, Raw fruits.
Dietary Sources of Starch.
Grains- Rice ,Wheat, Jawar, Bajra
Potatoes
Beetroot.
Sago (Tapioca)
Vermicelli
Suji.
Raw Mangoes
Biomedical Importance Of Starch
Starch is a storage form of Glucose
and serves as reservoir of energy in
plants.
To humans Starch is a predominant
form of dietary Carbohydrate
ingested through foods which has
high dietary and calorific value.
Digestion of Starch
In mouth- by salivary Amylase
In intestine -by pancreatic Amylase
Amylase cleaves, (1-4) glycosidic
bonds of Amylose and Amylopectin and
releases Maltose and Isomaltose.
Maltose and Isomaltose is then
digested by Maltase and
Isomaltase to release free Glucose
units.
Thus Starch on digestion gives
thousands of free Glucose units
which have high calorific value.
Glycogen
Animal Homopolysaccharide
Animal Starch
Chemistry Of Glycogen
Glycogen is chemically
Glucosan.
Repeating Unit ?
D Glucose (25-30 thousand
Glucose units)
Glycogen is like Amylopectin
structure ,but it is highly branched
Branching points appear after
every 8-10 Glucose units, linked by
(1-6) glycosidic bond.
Linear structure has Glucose linked
with (1-4) glycosidic bond.
Glycogen
Glycogen has more a(16)
branches.
The highly branched structure
permits rapid glucose release
from glycogen stores, in muscle
during exercise.
Source/Occurrence Of Glycogen
Glycogen is present in
animal-
Liver (75 gm)
Muscle (125 gm).
Non-Veg diet is a source
of dietary Glycogen to
human beings, which has
high dietary and calorific
value.
After well fed condition, free
and excess of Glucose is
condensed to Glycogen via
Glycogenesis.
Rate of Glycogen synthesis ?
Liver- 6-8 %,
Muscle 1-2 %
Glycogen is broken
down to Glucose via
Glycogenolysis when
body Glucose lowers in
fasting and starvation
condition.
Biomedical Importance Of
Glycogen
Glycogen is a storage form of
Glucose in animal and human body
after well fed conditions.
It serves as reservoir of Glucose
which can be used in emergency
conditions
( Fasting /Between meals )
Glucose stored in
polymeric/condensed
form minimizes osmotic
effects and occupy less
space.
Glycogen produces less
osmotic pressure and occupy
small space.
Glycogen is sparingly soluble in
water.
On Iodine reaction Glycogen
gives deep red color.
Dietary Glycogen in
GIT is digested by
- Amylase to Maltose
and Isomaltose and
finally to thousands of
Glucose Units.
Liver Glycogenolysis
in Human body
regulates Blood
Glucose levels in
fasting condition.
Muscle
Glycogenolysis
provides energy for
muscle activities in
fasting condition.
Cellulose
Non digestible carbohydrate
Cellulose serve as dietary
Fiber.
Chemistry Of Cellulose
Cellulose is a Glucosan
Repeating Unit - D Glucose.
(approx 2,500- 14,000 ).
Cellulose is a linear ,unbranched
structure where D Glucose units
repeatedly linked by (1-4 ) glycosidic
bonds.
Source/Occurrence Of Cellulose
Cellulose is an abundant carbohydrate of
nature exclusively present in Plants cell wall.
Dietary rich sources of Cellulose
Whole Grains (outer covering)
Green leafy vegetables
Cabbage, Cucumber
Legumes, Nuts, Beans
Dates
Fruits and Vegetable salads.
Biomedical Importance of
Cellulose
In plants Cellulose
present in cell wall
provides structural
and mechanical
support.
Wood, cotton and
paper are composed
primarily of cellulose.
In humans, dietary
Cellulose is not digested
and absorbed.
Enzyme Cellulase is absent
in human GIT.
Cellulose has no calorific
value.
Dietary
Cellulose in
humans serves
as dietary fiber.
Cellulose has Effect on Fecal Mass
Formation
Cellulose acts as a roughage.
It holds water ,helps in forming soft and bulky
feces.
Increases intra luminal pressure.
Reduces transit time of feces to remain in gut.
Eliminates daily, metabolic wastes and toxins
out of the body, through feces.
Defecation with greater ease and good
frequency.
Cellulose prevents
constipation, and reduces risk
of :
vcolon cancer
vvaricose veins
v diverticulosis of intestine
v hemorrhoids
Cellulose reduces the absorption
of :
Glucose
Cholesterol
Ameliorate the conditions of :
?Diabetes mellitus
? Atherosclerosis respectively.
Cellulose being non
calorific and
possessing high satiety
value helps in
managing obesity in
humans.
For maintenance of good health
ingest dietary fibers.
RDA for dietary fiber to
maintain good health:
Adults= 20-25 gm/day.
Children's= 5-10 gm/day.
Disadvantage of dietary
Cellulose-
It decreases absorption of
minerals.
Dextrin
Intermediate
hydrolytic
product of Starch
digestion
Chemistry Of Dextrin
Dextrin is a Glucosan
Repeating Unit - D Glucose.
Dextrin is less complex than starch
structure.
Dextrin is broken Starch molecule.
Types Of Dextrin
Amylodextrin -Violet to Iodine reaction
Erythrodextrin- Red to Iodine reaction
Achrodextrin -Colorless to Iodine reaction.
Source/Occurrence of Dextrin
In human GIT Dextrin is obtained as
an intermediate hydrolytic product
of Starch digestion by the action of
-Amylase activity.
Dextrin is Present in commercially
prepared infant foods.
Biomedical Importance Of Dextrin
Dextrin has mucilage
nature(sticky) hence used as
binding and adhesive agent.
Dextrin is used as infant food.
Dextran
Dextran is a Bacterial
Homopolysaccharide
Chemistry Of Dextran
Dextran is a Glucosan
Repeating Unit ? D Glucose.
Highly branched, complex, network
like structure
Glucose units linked by
(1-4) ,(1-6) and (1-3) glycosidic
linkages.
Source/Occurrence Of Dextran
Dextran is obtained from
Sucrose solution
incubated with bacteria
Leuconostoc
mesenteroides
Biomedical Importance Of Dextran
Dextran solution is high molecular
weight, viscous solution with
osmotic pressure equivalent to
plasma Albumin.
Dextran maintains blood volume
and osmotic pressure.
Dextran solution is used as
Plasma substitute/plasma
volume expander
Dextran infusion manages a
hemorrhagic case and
prevent from
hypovoluemic shock.
Sephadex
Sephadex is a modified Dextran.
The dextran macromolecules are cross-
linked to give a three-dimensional
network of polysaccharide chains.
Insoluble in water but absorb water
and swell.
Uses: In Chromatographic separation.
Fructosan
Homopolysaccharide
with repeating units as
Fructose.
Inulin
Diagnostic Carbohydrate
Diagnoses Kidney Function-
GFR of Kidney.
Chemistry Of Inulin
Inulin is a Fructosan
Repeating Unit-
D Fructose units (33-35 units)
Repeatedly linked by
(1-2) glycosidic bonds.
Source/Occurrence Of Inulin
Naturally present in Plants
Roots and tubers of
Dandelions
Onion and Garlic bulbs
Chicory Plant.
Biomedical Importance Of Inulin
Inulin is non digestible and non
absorbable form in human GIT, hence
have no calorific value.
Inulin solution infused intravenously
during Inulin Clearance Test,
checks Glomerular Filtration Rate
(GFR) of Kidney (120-125 ml/min).
Heteropolysaccharides
Heteropolysaccharides are type
of Polysaccharides composed of
more than 10 different
Monosaccharide units or
their derivatives repeatedly
linked by glycosidic bonds.
Animal Heteropolysaccharides
Mucopolysaccharides (MPS)
Human Heteropolysaccharides
Animal Heteropolysaccharides
Glycosaminoglycans (GAGs)
Mucopolysaccharides
were first isolated from
Mucin hence the name
Mucopolysaccharides.
Mucopolysaccharides
chemically composed of more
than 10 Monosaccharide units
and its derivatives repeatedly
linked by glycosidic bonds.
Mucopolysaccharides
are complex, long,
linear, unbranched,
polyanionic.
The Glycosaminoglycans has
Disaccharide repeating unit
linked by glycosidic bonds of
Uronic Acid
Amino Sugar
Uronic Acid ?
Glucuronic acid /Iduronic acid
(Iduronic acid is 5' Epimer of Glucuronic acid)
Amino Sugar-
Glucosamine / Galactosamine
(Acetylated or Sulfated or Both)
Jeanloz suggested the
term GAG's as these
biomolecules has
amino sugars as
repeating units.
Properties of GAG's
GAG's are polyanionic and acidic due
to presence of
?COO- and SO4-- -
GAG's are hydrophillic and attract
water and helps in distributing
water.
MPS due to repulsion of
charges:
It appear slippery or sticky
in appearance/mucus like
secretions
It expand to occupy large
space.
MPS/GAG's imparts following
physical properties-
Turgor
High Viscosity
High Density
High Buoyancy.
Body Mucopolysaccharides
Acidic Non Sulfated MPS:
Hyaluronic Acid
Acidic Sulfated MPS:
Heparin
Heparan Sulfate
Chondritin Sulfate
Dermatan Sulfate
Keratan Sulfate
Neutral MPS:
Blood Group Substances
Hyaluronic Acid
Acidic Non sulfated MPS
Repeating Disaccharide Unit
Glucuronic acid
NAcetylGlucosamine.
Occurrence and Functions Of
Hyaluronic acid
Hyaluronic acid is present as
ground substance/cementing
substance in extra cellular
spaces of connective tissue.
Hyaluronic acid in
synovial fluid of joints
and vitreous humor of
eye serve as lubricant
and shock absorbant.
Hyaluronic acid
around ovum
gives protection.
Hyaluronic acid
plays role in cell
migration during
morphogenesis.
Enzyme "Hyaluronidase " hydrolyses
Hyaluronic acid.
Hylauronidase present in head of sperm
, hydrolyzes the Hyaluronic acid present on
ovum which facilitates its penetration
and fertilization.
Snake venom is rich in Hyaluronidase,
thus snake bite hydrolyzes and liquifies the
Hyaluronic acid present in extracellular
spaces of cells ( TOXIN )
Heparin
Most Acidic Sulfated MPS.
Disaccharide Repeating Unit:
Glucuronate sulfate ( minor
)
Iduronate sulfate (major)
N-Glucosamine Sulfate.
?Heparin, a soluble
glycosaminoglycan found in granules
of mast cells and is highly sulfated.
?Heparin has an extended helical
conformation.
Occurrence and Functions Of
Heparin
Heparin present in blood vessels,
Liver, Lung, Spleen and
Monocytes
Heparin is a natural anticoagulant.
Prevents intravascular blood
coagulation by inactivating
clotting factor IX and XI.
When released into the
blood, it inhibits clot
formation by interacting
with the protein
antithrombin.
Heparin is an indirect
Thrombin inhibitor .
Rapid inactivator of Thrombin.
Thus antithrombotic agent.
Prevents intravascular blood
clotting.
Heparin releases
enzyme Lipoprotein
Lipase from endothelial
lining and serve as
coenzyme for it.
Lipoprotein Lipase is
Lipid clearing Enzyme
of blood.
Therapeutic Use of Heparin
Heparin is infused to prevent and
treat thrombous located in
vein/artery in MI cases.
Deep Vein Thrombosis.
Pulmonary Embolism
Strokes
Heparin(LMW Heparin)
injections are given to
M.I patients
To liquify blood ,prevent
thrombosis and clear
blood with lipids.
Heparan Sulfate
Acidic Sulfated Mucopolysaccharide
Disaccharide repeating units
Glucuronate Sulfate (major)/ Iduronate
Sulfate (minor)-N Acetyl Glucosamine
Occurrence and Functions Of
Heparan Sulfate
Heparan Sulfate present on
extracellular cell surfaces or
plasma membranes and serves
as receptors
Participate in cell growth, cell
adhesion, and cell -cell
communication.
Heparan sulfate in basement
membrane of kidney helps in
determining charge selectiveness
of Glomerular filtration.
Heparan sulfate are also
components of aorta, liver,
fibroblasts, synaptic and vesicles.
Chondritin Sulfate
Acidic Sulfated
Mucopolysaccharid
e
Disaccharide Repeating Unit
Glucuronate-
N ?Acetyl Galactosamine ?Sulfated.
Chondritin Sulfate A-4 sulfated.
Chondritin sulfate C-6 sulfated.
Occurrence and Functions Of
Chondritin Sulfate
Chondritin Sulfate is present in
connective tissues-bones,
cartilage, tendons .
It gives mechanical strength,
compressibility and support to
connective tissues.
Chondritin sulfate
present in cornea
give over all shape to
eye.
Dermatan Sulfate
Acidic Sulfated Mucopolysaccharide.
Chondritin sulfate-B / -Heparin
Disaccharide Repeating Unit
L-Iduronate-
N-AcetylGalactosamine-sulfated
Occurrence and Functions Of
Dermatan Sulfate
Dermatan sulfate especially present in
skin, blood vessels and heart valves
gives mechanical strength and
structural support to these tissues.
Dermatan sulfate plays structural
role in sclera of eye.
Keratan Sulfate
Acidic Sulfated Mucopolysaccharide
Keratan Sulfate is a MPS without Uronic
acid instead contains Galactose.
Disaccharide Repeating Unit
Galactose-N-Acetyl Glucosamine ?sulfated
Keratan sulfate present in cartilage,
aorta walls, gives structural
supports and mechanical strength.
Keratan sulfate present in cornea
and lens of eye has role in lens
transparency and shape of eye.
Blood Group Substances
Blood group substances are Neutral MPS
Components of Blood Group
substances
Galactose, Fucose,
N-Acetyl Glucosamine, N-Acetyl
Galactosimne
Blood group substances
neutral MPS, present
on cell surfaces of
Erythrocytes serves as
blood group antigens.
Applied aspects of
Mucopolysaccharides/ GAGs
On ageing or during
pathogenesis the biosynthesis of
certain specific
Mucopolysaccharide
/Glycosaminoglycan is either
increased or decreased leading
to disorders and manifestations.
Tumors cells-
Increased Hyaluronic acid
(Increases cell migration)
Decreased Heparan Sulfate
(Decreases cell adhesion)
This Increases Metastasis
Rheumatic Arthritis-
Rheumatic nodule shows
increased Hyaluronic acid
deposition.
Atherosclerotic
plaque-
Excess production of
Dermatan Sulfate
Decreased production
of heparin.
Osteoarthritis-
Imbalance biosynthesis
of Hyaluronic acid,
Chondritin Sulfate and
Keratan Sulfate
Mucoproteins
Or
Proteoglycans
Mucoproteins/
Proteoglycans
are conjugated
Proteins.
Mucopolysaccharides/
Glycosaminoglycans
(Prosthetic group) are never
found free but always covalently
linked to a core protein by N-
Glycosidic/O-Glycosidic bond to
formMucoproteins/Proteoglycan
O-Glycosidic /N-Glycosidic bond
Glycosaminoglycans
Core
Protein
Mucoproteins have
Carbohydrate
content more than
10 % and are viscous
in nature.
Mucoproteins/
Proteoglycans are
more complex,
viscous, highly dense,
molecular aggregates.
GAG chains
core
protein
Proteoglycans are
composed of as many as
200 GAG chains covalently
bonded to a core protein
via Serine/ Threonine side
chains.
Molecular weight range: 105 ? 107 Daltons.
GAG chains linked:
Hyaluronic acid
Chondroitin sulfate
Heparan sulfate
Dermatan sulfate
Keratan sulfate
Examples of Proteoglycans
Aggrecan
(Hyaluronate-Core Protein non
covalently linked In Cartilage)
Biglycan
Beta Glycan
Decorin
Serglycin
Syndecan
Perlecan
Versican
Mucoproteins has properties like of
Mucopolysaccharides.
Mucoproteins widely distributed in
Extracellular Matrix of connective
tissues ( Bone and Cartilage).
Mucoproteins provide structural
framework and mechanical
support to those tissues which
constitute them.
Mucopolysaccharidoses
Mucopolysaccharidoses are group
of inherited disorders related to
defective Mucopolysaccharide
metabolism.
Cause:
Impaired degradation of GAG's
by defective Lysosomal
enzymes.
Half life period of GAG's
is short.
3-10 days for most of the
GAG's.
120 days for Keratan ?SO4.
Biochemical Alterations :
No catabolism of GAG's.
Abnormal widespread intra
Lysosomal deposition of GAG's
in functional tissues affecting
their functions.
Excretion of MPS in Urine.
Mucopolysaccharidoses
Syndrome
Enzyme Defect
Accumulated GAG
Type
(Lysosomal)
I
Hurler's
- L Iduronidase
DS, HS
Syndrome
II
Hunters'
Iduronate Sulphatase
DS , HS
Syndrome
III
Sanfilippo's
Heparan Sulphatase
HS
Syndrome
IV
Morquio's
Galactosamine
KS, CS
Syndrome
Sulphatase.
V
Scheie's
L- Iduronidase
DS
Syndrome
VI
Maroteaux
N-
DS
Lamy
AcetylGalactosamine
Syndrome
-4-sulphatase.
VII
SLY's
- Glucuronidase.
DS, HS
IX
Naowicz
Hyaluronidase
HA
Syndrome
All Mucopolysaccharidoses
are of autosomal recessive
inheritance.
Hunter's Syndrome is of X
linked inheritance.
Consequences /Clinical Manifestations:
Lysosomal vesicles become swollen with
incomplete degraded GAG's in it.
Coarse facial features.
Thick skin, skeletal damage.
Corneal Opacity, Hearing loss.
Mental Retardation.
Hepatosplenomegaly.
Cardio pulmonary defects.
Growth deficiency and skeletal dysplasia.
Diagnosis:
Measuring concentration of
Lysosomal Hydrolases.
Detection of GAG in Urine.
Plant Heteropolysaccharides
Agar-Agar
Agar is obtained from red algae.(Sea weed)
Agar is formed of two main components,
Agarose and Agaropectin.
Agarose is a neutral galactose polymer, free
from sulfate.
Agaropectin is formed of galactose and
galacturonic acid units partially esterified
with sulfuric acid.
Uses of Agar
Preparation of bacteriological
culture media.
Emulsifier, thickener for ice
creams,puddings.
Laxative-for treatment of ulcers
and chronic constipation.
Pectin
Obtained from apple pomace and
inner portion of citrus rind.
Form viscous solutions in water.
Composed of Arabinose, Galactose
and Galactouronic acid.
Average molecular weight 100,000-
250,000.
Uses Of Pectin
Pectin is topically applied as a paste in
cases of burns and ulcers.
It acts as a detoxifying agent by
conjugation with toxins.
It is of great importance in treatment of
diarrhea and dysentery.
It is used as a gel and emulsion stabilizer
and in manufacture of jellies and jams.
Glycoproteins
Glycoproteins are conjugated
proteins
Where the prosthetic group,
branched or unbranched chain of
Oligosaccharide
Is linked to a protein backbone with
O-Glycosidic or N-Glycosidic
linkage.
O-Glycosidic/N-Glycosidic bonds
Oligosaccharide
Chain
Protein
Carbohydrate
content of
Glycoprotein is
less than 10%.
N-linked saccharides are
attached via the amide
nitrogens of Asparagine
residues .
O-linked saccharides are
attached to hydroxyl groups
of Serine, Threonine or
hydroxy Lysine .
N-linked Glycoproteins
O-linked Glycoproteins
Oligosaccharides have
different sequences of monosaccharide units
different sequences of glycosidic linkages.
different kinds of branching.
This imparts a very high degree of
diversity for Oligosaccharides and
their structure-function relationships
Varied glycosidic linkages in
Oligosaccharide chain of
Glycoproteins create enormous
variability required for
identifying different cells.
This variation is the basis for
the mechanism of cell-cell
recognition.
N-acetylneuraminate (N-acetylneuraminic acid,
also called sialic acid) is often found as a terminal
residue of oligosaccharide chains of glycoproteins.
Sialic acid imparts negative charge to
glycoproteins, because its carboxyl group tends to
dissociate a proton at physiological pH, as shown
here.
Significance of Oligosaccharide
chains in Glycoproteins :
Stabilizes the Proteins against
denaturation.
Protect Proteins from Proteolytic
degradation.
Enhances the solubility.
Serve as a recognition signals to
facilitate cell-cell interaction.
Glycoproteins of human body:
All plasma proteins are
Glycoproteins.
Structural protein Collagen of
bone is glycoprotein.
Enzymes- Ribonuclease-B,
Alkaline Phosphatase.
Hormonal receptors on cell
membranes.
Glycophorin is a major integral
membrane Glycoprotein of RBC's.
Lubricant Mucin.
Proteins-Transferrin and
Ceruloplasmin are Glycoproteins.
Glycoproteins and Glycolipids are
Glycocalyx of cell membranes.
Clotting factor-Prothrombin.
Hormones-Thyroglobulin,
Erythropoietin, TSH, HCG.
Immunoglobulin- IgG, IgA, IgD,
IgE, IgM.
Biomedical Importance's of
Carbohydrates.
Energy Aspects of
Carbohydrates/Carbohydrates
have dietary and calorific value
Carbohydrates serve as primary
source of energy, with calorific
value 4Cal/gm.
Carbohydrates of Dietary and
Calorific value
Starch (Predominant-Grains, Potatoes, Vegetables)
Glycogen (Non Veg diet)
Sucrose (Common table Sugar)
Lactose (Milk and Milk Products)
Maltose (Starch digestion, Malt)
Glucose (Glucon-D, Fruits)
Fructose (Fruits, Honey)
Reserve Store Capacity Of
Carbohydrates:
Dietary Carbohydrate (Glucose)
when free and excess in the body
get transformed to reserve store
forms Glycogen and Triacylglycerol
(Fat), which are utilized during
emergency conditions.
Non digestible Carbohydrate-
Cellulose serves as dietary
fiber :
Cellulose act as roughage and
prevents from constipation.
Cellulose has no calorific value
hence help in management of
obesity.
Carbohydrates as Dietary Fiber
Cellulose
Pectin
Lignin
Agar
Gum
Hemicellulose
Carbohydrates are components of
Mucoproteins
Glycoproteins
Glycolipids
Blood Group Substances
Structural and other functional
roles of Carbohydrates :
Mucoproteins present in connective
tissues provide structural and
mechanical support.
Hyaluronic acid in synovial fluid of
joints and vitreous humor of eye
serve as lubricant and shock
absorbent.
Heparin serves as natural
anticoagulant and prevents
intravascular coagulation.
Heparan sulfate present on cell
surfaces act as recognition elements on
cell membrane ,cell receptors and
helps in cell growth, cell adhesion,
and cell-cell communication.
Pentose sugars Ribose and
Deoxyribose are
components of Nucleotides
which build Nucleic acids ?
RNA and DNA and other
nucleotide coenzymes.
Diagnostic Value of Carbohydrate:
Fructosan Inulin, is used
to carry out:
Inulin Clearance Test,
which checks, Glomerular
Filtration Rate of kidney.
Therapeutic Value of
Carbohydrates:
Cardiac Glycosides Digoxin- used
to treat cardiac insufficiency.
Glycosides Ovabain and Phlorizin
- used in treatment of Diabetes
mellitus.
Glycosides Streptomycin
,Erythromycin used to treat
bacterial infections.
Mannitol- Serve as osmotic diuretic used
in treatment of Acute Renal Failure.
Lactulose -Relives Hyperammonaemia in
patients of Hepato Encephalopathy.
Dextran- Used as plasma substitute in
hemorrhagic cases to prevent
hypovoluemic shock.
Hyaluronan- Used to treat osteoarthritis.
Sr.No
Reducing Sugars
Non Reducing Sugars
1.
Reducing sugars possess free or potential
Non reducing sugars does not
aldehyde or ketone group in it's structure
possess free or potential
aldehyde or ketone group in it's
structure
2.
Reducing sugars show reducing property .It
Non Reducing Sugars does not
form an Enediol in alkaline medium which then
show reducing property.
reduces certain metallic ions of copper, bismuth
3.
Reducing Sugars answers following tests
Non Reducing Sugars answers
positively- Benedicts, Fehlings,
following tests negatively-
Nylanders, Osazone Tests
Benedicts, Fehlings, Nylanders,
Osazone Tests
4.
Reducing sugars exhibit Mutarotation
Non Reducing sugars does not
show Mutarotation
5.
Examples of Reducing Sugars -
Examples of Non Reducing Sugars
All Monosaccharide's are Reducing Sugars- ex
or
Ribose, Glucose, Fructose etc
Non reducing Disaccharide-
Reducing Disaccharides-Lactose, Maltose
Sucrose, Trehalose.
Sr. No
Amylose
Amylopectin
1.
Starch granule contains 15-20% of
Starch granule has 80-85% of
Amylose.
Amylopectin.
2.
Amylose is soluble and present in
Amylopectin is insoluble part present at
inner core of starch granule.
periphery of starch granule.
3.
Amylose is a linear, unbranched
Amylopectin is a branched structure,
structure composed of 200-1000
composed of more than 1000 D
D Glucose units repeatedly linked by Glucose units linked by (1-4)
(1-4) glycosidic bonds
glycosidic bond in linear and (1-6)
glycosidic bond at branching point,
which appears after every 25-30
Glucose residues.
4.
Molecular weight of Amylose is
Molecular weight of Amylopectin is 1
400000
million .
5.
Amylose gives blue color with Iodine Amylopectin gives reddish violet color
test.
with Iodine test.
Sr. No
Starch
Glycogen
Starch is Plant Homopolysaccharide. Glycogen is animal Homopolysaccharide
1.
2.
Starch is composed of Amylose
Glycogen is highly branched structure
(Linear)&Amylopectin (Branched)
with branching points appearing after
every 8-10 Glucose residues.
3.
Starch is composed of 4000-7000
Glycogen is composed of 6000-30,000
Glucose units.
Glucose units.
4.
Starch is a storage form of Glucose Glycogen is storage form of Glucose and
and reserve food material in plants.
reserve form of energy in animals and
human beings.
5.
Starch is stored in roots, tubers,
Glycogen is stored in Liver and Muscles
seeds, raw fruits of plants.
of animal and human body.
6.
Starch serves as predominant dietary Glycogen is dietary form of Carbohydrate
Carbohydrate form in Veg and
only in Non-Veg eaters.
Nonveg eaters.
7.
Starch with Iodine test gives deep
Glycogen with Iodine test gives deep red
Blue color.
color.
Sr.No
Starch
Cellulose
Starch is a Glucosan composed of
Cellulose is a Glucosan composed of
1.
DGlucose units, repeatedly linked DGlucose units ,repeatedly linked by
by (1-4) glycosidic bonds in linear (1-4) glycosidic bonds.
and (1-6) glycosidic bonds at
branching point.
2.
Starch present in plants serve as
Cellulose present in plant cell wall
storage form of Glucose and reserve provides structural frame work to plants.
food material.
3.
Dietary Starch is digested in human Dietary Cellulose is not digested in
GIT by enzyme Amylase.
human GIT due to absence of enzyme
Cellulase.
4.
Starch has dietary and calorific value. Cellulose has no calorific value but serve
as dietary fiber.
Sr.No
Dextrin
Dextran
1.
Dextrin is plant
Dextran is bacterial
Homopolysaccharide
Homopolysaccharide.
2.
Dextrin is an intermediary
Dextran is a Glucosan obtained
hydrolytic product of Starch from Sucrose solution incubated
digestion.
with Leuconostoc mesenteroides.
3.
Structure of Dextrin contains Structure of Dextran contains (1-
(1-4) & (1-6) glycosidic 3),
bonds.
(1-4) & (1-6) glycosidic bonds.
4.
Dextrin solution is used in
Dextran solution is used as plasma
commercially prepared infant volume expander in relieving
feedings and mucilage for
hypovoluemic shock in cases of
pasting stamps.
hemorrhage.
QUESTIONS
Q.1.Define carbohydrates.
Enumerate the biomedically
important Carbohydrates.
Q.2.Classify and sub classify
Carbohydrates with terms and suitable
examples.
Q.3. Simple Sugars /Monosaccharides
Q.4. Define stereoisomerism.
Enumerate the stereoisomers of
Glucose.
Q.5. D & L Glucose
Q.6. Anomers
Q.7. Epimers
Q.8. What is optical activity? Give
its type.
Q.9. Mutarotaion
Q.10. Chemical Reactions of Glucose
/Reactions of Monosaccharides.
Q.11. Write 8 derivatives of
Monosaccharides and their
importance.
Q.12. Glycosides and its
importance.
Q.13. Osazones Reaction. Draw the
structures of Glucosazone,
Fructosazone, Lactosazone &
Maltosazone.
Q.14. Explain why Glucosazone &
Fructosazone show same shape.
Q.15. Disaccharides (Definition,
Types, Components, Glycosidic bonds,
Sources ,Biomedical Importances).
Q.16. Invert sugar,
Q.17. Lobry- de- Bruyn- Von
Ekenstein transformation
Q.18. Haworth and Fischer's projection of
Glucose.
Q.19. Why sucrose is a non-reducing
sugar?
Q.20. Homoglycans /
Homopolysaccharides
Q.21. Glycosaminoglycans /Acid
Mucopolysaccharides (structure &
function)/Animal Heteropolysaccharides
Q.22. Inulin and its importance.
Q.23. Differences between
Dextrin and Dextran.
Q.24. Cellulose & its
importance.
Q.25. Distinguish between
reducing & non-reducing sugars.
Q.26. Write the components and
glycosidic linkages involved in following
carbohydrates.
Sucrose
Maltose
Lactose
Glycogen
Cellulose
Amylose
Amylopectin
Q.27. Mucoproteins.
Q.29. Biomedical Importance
of carbohydrates.
Q.30. Mucic acid test.
Q.31. Test's to check the
present of reducing sugars.
Q.32. Glycosidic bonds.
Q.33. Glycoproteins of human body.
Q.34. Differentiate between Starch
and Cellulose.
Q.35 Differentiate between Starch
and Glycogen.
Q.36 Mucopolysaccharidoses.
Q.37 Diagnostic and therapeutic
uses of Carbohydrates.
THANK YOU
This post was last modified on 05 April 2022