ProteoglycansGlycoproteinsLipoproteinsProteolipidNucleoproteinLipopolysaccharides

1. Proteoglycans
Glycoproteins
Lipoproteins
Proteolipid
Nucleoprotein
Lipopolysaccharides
(Dr.) Mirza Salman Baig
Assistant Professor (Pharmaceutics)
AIKTC, School of Pharmacy,New Panvel
Affiliated to University of Mumbai (INDIA)

2. Proteoglycans
• Proteoglycans are macromolecules of
the cell surface or extracellular matrix
in which one or more
glycosaminoglycan (heparin
produced by mast cells) chains are
joined covalently to a membrane
protein or a secreted protein.
• The glycosaminoglycan moiety
commonly forms the greater
fraction (bymass) of the proteoglycan
molecule
• Proteoglycans are major components of
connective tissue such as cartilage

3. Proteoglycans
• They form extracellular matrix,
between cells in an organism.
• They form connective tissue such as
collagen and aggrecan .
• They are also involved in binding
cations (such as sodium, potassium
and calcium) and water, and also
regulating the movement of molecules
through the matrix.
• They serve as joint lubricants in
biological system.

4. Glycoproteins
• Glycoproteins have one or several
oligosaccharides joined covalently to a
protein by N-glycosidic linkage/ O-glycosidic
linkage via Aspargine /Serin/Threonine.
• They are found on the outer face of the
plasma membrane, in the extracellular
matrix, and in the blood.
• Inside cells they are found in specific
organelles such as Golgi complexes,
secretory granules, and lysosomes.
• The oligosaccharide portions of
glycoproteins are less monotonous (more
complex) than proteoglycans
• Sugar component in minor

5. Glycoproteins
• Glycoproteins contain covalently linked
oligosaccharides that are smaller but
more structurally complex, and
therefore more information-rich,
than glycosaminoglycans.
• They form highly specific sites for
recognition and high-affinity binding by
other proteins.

6. Lipopolysaccharides
• Lipopolysaccharides are the dominant
surface feature of the outer
membrane of gram-negative bacteria
such as Escherichia coli and
Salmonella typhi.
• These molecules are prime targets
of the antibodies produced by the
vertebrate immune system in
response to bacterial infection.
• Therefore important determinants of
the serotype of bacterial strains
(serotypes are strains that are
distinguished on the basis of antigenic
properties).

7. Lipopolysaccharides
• The lipopolysaccharides of some
bacteria are toxic to humans and
other animals
• They are responsible for the
dangerously lowering blood
pressure that occurs in toxic shock
syndrome resulting from gram
negative bacterial infections

8. Lipoproteins
• Molecular complexes of lipid with
protein
• they are transport vehicles for lipids
• Types
1.Chylomicrons
2.Very Low density lipoprotein (VLDL)
3.Low density lipoprotein (LDL)
4.High density lipoprotein (HDL)
5.Free fatty acid albumin complexes

9. Structure of lipoprotein
• Neutral lipid (triglycerides) core
sorrounded by phosphoipid shell
• Polar portion of phospholipid and
cholestrol are exposed on surface
• Hence, Lipoprotein is soluble in
aqueous medium

10. Apolipoprotein (Apoprotein)
• It is protein component of lipoprotein
• Functions
– Act as structural component of
lipoprotein
– Recognise cell membrane surface
receptors
– Activate enzymes involved in lipoprotein
metabolism

11. HDL
• Synthesized in liver
• It contain Cholesterol, Phospholipid
(lecithin), Aprotein.
• HDL is good cholesterol as it play
cardioprotective role
• It act as antioxidant (due to
presence of enzyme paroxanase) for
LDL
• Chance of heart attack is reduced

12. Proteolipids
• Proteolipids can be defined as all
proteins containing covalently bound
lipid moieties, including fatty acids,
isoprenoids, cholesterol and
glycosylphosphatidylinositol.

13. Proteolipid
• In year 1951, proteins that were
soluble in organic solvents such as
chloroform-methanol were found in
rat brain myelin by Folch and Lees
who coined the term ‘proteolipid’
• It is found in plasma

14. Proteolipids
Types
• Saturated fatty acid components with
only myristoyl moieties
• Saturated fatty acid components with
predominantly palmitoyl moieties
• Cholesterol covalently linked to
specific proteins, known as the
“hedgehog” signalling family [Ex:
sonic hedgehog (Shh) group]

15. Nucleoprotein
• Nucleoproteins are conjugated
proteins,
• Prosthetic group nucleoproteins are
nucleic acids
• Protein part of the nucleoproteins are
simple proteins, albumins, histones
and protamins

16. Importance of Nucleoproteins
• Closely associated with the
chromosomes of the cells
• Act as co-factors to the enzymes –
catalytic activities
• Play a role in the energy transfer in
living organisms

17. Properties of Nucleoproteins
• Soluble in alkalis and hot water
forming salts
• Insoluble in alcohol
• Slightly soluble in cold water
• Precipitated by acetic acid
• Found cells with big nuclei like thymus,
liver, spleen, kidney, and pancreas
also found in bacteria, bacteriophages