2. • Glycolipids they do not contain phosphate.
• Essential components of cell or plasma membranes (outer leaflet) &
also most abundant in nervous tissues
Glycolipids
Cerebrosides
Sulfatides
Globosides
Gangliosides
Ceramide Carbohydrate
Glycolipids
3. CEREBROSIDES
• High conc in white matter of brain & Myelin sheaths of nerves.
• 4 types, differing only with respect to the type of fatty acids
Monosaccharides
Types of cerebrosides Fatty acid
Kerasine Lignoceric acid
Cerebron Cerebronic acid
Nervon Nervonic acid
Oxynervon Hydroxy derivatives of Nervonic acid
4. Simplest glycolipids –
Glucocerebrosides (Ceramide + Glucose) – Extra neural (non-
neural) tissues.
• Galactocerebrosides(Ceramide + Galactose) -Nerve tissue
membrane.
• It provide protective coating to each nerve and act as insulator
5. GLOBOSIDES
• Sugars are usually a combination of D- glucose , D-
galactose or N-acetyl galactosamine.
Ceramide
6. SULFATIDES
• It is widely distributed in plants.
• Found in chloroplast & chromatophores of photosynthetic
bacteria.
• Most common sulfatide is Sulfogalactoceramide, which is found in
nerve tissue.
Ceramide + Monosaccharides + Sulfate
7. GANGLIOSIDES
• Imp Gangliosides present in the brain - GM1, GM2, GM3, GD & GT.
• (G – Gangliosides, While, M- mono, D- di & T- tri sialic acid
residues & number denotes the migration in chromatography or
electrophoresis).
• Simplest Gangliosides found in tissue is GM3
Ceramide + Oligosaccharides + N–acetyl neuraminic acid
8. Functions of Glycolipids
Involved in cell membrane receptors for certain
polypeptide hormones
Cell interactions, growth &
development
Antigenic property
(e.g., blood group antigens)
Act as surface receptors for some toxins &
viruses
Mediating cell-cell recognition
12. CLASSIFICATION
According to their physical & chemical properties
Based on the density:
Separated by ultracentrifugation into 4 types
• Chylomicrons
• Very low density lipoproteins (VLDL)
• Low density lipoproteins (LDL) & IDL
• High density lipoproteins (HDL) – HDL-1, 2 & 3
13. Based on the electrophoretic mobility
In origin – chylomicrons
Migrating into β-globulin region – β-lipoprotein (LDL)
pre-β-globulin region –pre -β-lipoprotein (VLDL)
α-globulin region – α-lipoproteins (HDL)
15. Families Chylomicrons LDL VLDL HDL
Lp-A A-I & II ---- ---- A-I & II
Lp-B Apo-B48 Apo-B48 Apo-B100 ---
Lp-C C-I, II, III C-I, II III C-I, II, III C-I, II, III
Lp-D --- -- -- HDL -3
Lp-E Apo-E Apo-E Apo-E Apo-E
Apolipoproteins
Major protein components of lipoproteins - Apo-proteins
These are classified by (A, B, C, D & E)
Sub groups given in roman numeral depending on the emerge
from a chromatographic column.
16. Apoprotein Functions
A-I In plasma; activates LCAT
A-II Enhances hepatic lipase activity
B-48 & B-100 Binds to LDL receptor
C-I Activate LCAT
C-II Activates lipoprotein lipase
C-III Inhibits lipoprotein lipase
D Also called as cholesterol ester transfer protein (CETP)
E Binds to LDL receptor
17. Functions of Apo-lipoprotein:
• Maintaining the structural integrity of the lipoproteins
• Responsible for recognition of particle by receptors
• Regulating certain enzymes, which act on the lipoproteins
18. FUNCTIONS OF LIPOPROTEINS
Chylomicron:
Transport of dietary triglyceride and cholesterol esters
from intestine to peripheral tissues and liver.
Very low density lipoprotein (VLDL):
Transports endogenous triglyceride from liver to
peripheral tissues.
19. LDL:
• It transports cholesterol from the liver to the peripheral
tissues, for use to form steroid hormones and building cell
membranes.
• But it also favors the deposition of cholesterol in arterial
walls and thus appears to play a role in disease of the blood
vessels and heart.
• It increased risk for myocardial infarction - Bad cholesterol
20. HDL:
• It transports free cholesterol from the peripheral tissue to the
liver, for using in energy metabolism, membrane
reconstruction and hormone function.
• HDLs also appear to prevent cholesterol from invading and
settling in the walls of arteries.
• It is an anti atherogenic agent.- Good Cholesterol