glucose amino glycans

GAGS

2. Glycosaminoglycans
(Heteropolysaccharides)

3. Learning Objectives
To identify the componentsof heteropolysaccharides
To know about some of the individualheteropolysaccharides
To understand the functionsof heteropolysaccharides
To know about thedisordersrelated to heteropolysaccharides

4. Also known as Glycosaminoglycans(GAGs)
Heteropolysaccharides are polysaccharides which yield
10 or moredifferent types of monosaccharidesortheir
derivativeson hydrolysis
Heteropolysaccharides

5. Present as polysaccharide chains of proteoglycans
Linked to the protein core via serine or threonine
(O-glycosidic linkage)
The chains are linear(unbranched)
Heteropolysaccharides

6. These are mostly composed of alternating units of
amino sugarsand uronic acids
Subclassified as
Mucopolysaccharides (Hyaluronic acid, Heparin)
Mucilages (Agar, vegetable gum, pectins, hemicellulose)
Heteropolysaccharides

7. Chondroitin
Sulfate
N-Acetyl -
D-
Galactosamine
D-GlucuronateCartilage, bone,
skin, cornea, blood
vessel walls
Glycosaminoglycan Amino SugarUronic Acid Tissue Distribution
Hyaluronic AcidN-Acetyl -
Glucosamine
D-GlucuronateConnective tissues
cartilage, synovial
fluid, Vitreous
humor, umbilical
cord
Heteropolysaccharides
Dermatan SulfatesN-Acetyl -
Glucosamine
L-Iduronate,
D-Glucuronate
Skin, heart valve,
tendon, blood
vessel wall.

8. Heparan SulfateD-GlucosamineD-Glucuronate
(major)
L-Iduronate
(minor)
Lung, blood vessel
walls, many cell
surfaces
Heteropolysaccharides
GlycosaminoglycanAmino SugarUronic Acid Tissue Distribution
Keratan sulfateN-Acetyl
Glucosamine
None (but
contains
D-Galactose)
Cartilage , Cornea,
Inter vertebral Discs
Heparin D-GlucosamineL-Iduronate
(major)
D-Glucuronate
(minor)
Lung, liver, skin,
intestinal mucosa
(mast cells)

9. As structural componentsof the extracellular (EC)matrix
Have specific interactions with collagen, elastin, fibronectin,
laminin, and other proteins of the matrix
Aspoly-anions, bind with poly-cations and cations
Contribute to the characteristicfullness/strengthof various
tissues
Heteropolysaccharides
Functions

10. Act assievesin the EC matrix
Facilitate cell migration(Hyaluronic acid)
Have role in compressibility of cartilagein weight–bearing
(Hyaluronic acid, Chondroitin sulfate)
Heteropolysaccharides
Functions

11. Play role in corneal transparency
(Karatan sulfate and Dermatan sulfate)
Have structural role insclera(Dermatan sulfate)
Act as anticoagulant(heparin)
Heteropolysaccharides
Functions

12. Are components of plasma membranes,
where they may act as receptorsand participates in
cell adhesionand cell interaction(e.g. Heparan sulfate)
Determine charge selectivenessof renal glomerulus
(Heparan sulfate)
Heteropolysaccharides
Functions

13. Mucopolysaccharidoses
Storage diseases related to glycosaminoglycans (GAGs)
Rare, inborn errorsof metabolism
Deficiencies / defects of enzymesthat degrade GAGs
result in a group of disorders called
mucopolysaccharidoses

14. These disorders are accompanied by one or more of the
following:
Somatic Skeletal changes
Mental retardation
Cardio Pulmonary problems
Hepato-splenomegaly
Corneal Clouding
Hearing loss
Mucopolysaccharidoses
Storage diseases related to glycosaminoglycans (GAGs)

15. Types of Mucopolysaccharidoses
Types Enzyme Defect Urinary MPS
MPS-1
(Hurler’s syndrome)
-L-Iduronidase
(a lysosomal hydrolase)
Dermatan SO
4
Heparan SO
4
MPS-II
(Hunters syndrome)
Iduronate Sulfatase -Do -
MPS-III
(San Filippo syndrome)
A.B. & C.
A.Sulfamidase
B.-N-acetyl-
Glucosaminidase
C.Acetyl-Transferase
Heparan SO
4

16. Types Enzyme Defect Urinary MPS
MPS-IV
(Morquio syndrome)
N –Acetyl –
Galactosamine –6 –
sulfatase
Keratan SO
4
Types of Mucopolysaccharidoses
MPS-V
(Scheie’s syndrome)
-L -Iduronidase Dermatan SO
4
MPS-VI
(Maroteaux Lamy
syndrome)
N –Acetyl –
Galactosamine –4 –
sulfatase
(Aryl sulfatase B)
Dermatan SO
4
MPS-VII
(Sly syndrome)
-Glucuronidase Dermatan SO
4
Heparan SO
4
ChondroitinSO
4

17. Hyaluronic acid derivatives
Several products are used in the management of
osteoarthritis symptoms
Others are used as ophthalmic surgical procedures
Gums
Widely used in the food and pharmaceutical industry
Used as: suspending agents, gelling agents, thickening
agents, emulsifiers, adhesives

18. Pectins
Pectins are heteropolysaccharides found in the pulp of
fruits (citrus, apples)
On hydrolysis pectins yield galacturonic acid, galactose,
arabinose, methanol and acetic acid
Used as gelling agents (to make jellies)