lipoproteins classification

1. Other complex lipids
• Sulfolipids, aminolipids, lipoproteins
• Lipoproteins contain fatty acid, alcohol and
protein
Eg. Plasma lipoproteins, membrane lipoproteins,
rhodopsin

2. Plasma lipoproteins
• Lipid + Apoproteins
• Lipoproteins function both to keep their
component lipids soluble as they transport them
in the plasma and to provide an efficient
mechanism for transporting their lipid contents
to (and from) the tissues
• The triacylglycerol and cholesterol carried by the
lipoproteins are obtained either from the diet
(exogenous source) or from de novo synthesis
(endogenous source

3. • Lipoproteins are composed of a neutral lipid
core (containing triacylglycerol, and
cholesteryl esters) surrounded by a shell of
amphipathic apolipoproteins, phospholipid,
and nonesterified cholesterol

4. Classification
• Plasma lipoproteins are further classified into
Chylomicrons,
VLDL,
IDL,
LDL,
HDL based on ultracentrifugation

5. Separation techniques of lipoprotein
Electrophoresis:
•TLC – separation of lipid classes
•GLC – separation of fatty acids

8. Characteristics of lipoproteins
Chylo VLDL IDL LDL HDL
Density g/L < 0.95 0.95-1.006 1.006-1.019 1.019-1.063 1.063-1.121
Diamtr(nm) 500 70 30 25 15
Electro-
mobility
Origin Pre-beta Broad beta Beta Alpha
Major lipid TAG PL TAG,CHOL CHOL CHOL
Apo proteins A, B-48,
C-II, E
B-100, C-II, E B-100, E B-100 A-I, C, E
FUNCTION TAG from
gut to
muscle and
adipose
tissue
TAG from
liver to
muscle
Cholesterol
from liver to
peripheral
tissues
Cholesterol
from
peripheral
tissue to
liver

9. Class Separation Composition Synthesis Functions Disorder
Chylomicrons UC: Lowest
density
E: Remain at
origin
Rich in TAG, apo
B-48 apoC.II
Small
Intestine
Transport of
dietary TAG to
the peripheral
tissues
Type I
hyperlipoproteinamia
and Diabetes mellitus.
Very low
density
lipoproteins
UC: Very low
density
E:Prebeta
position
Rich in TAG, apo
B-100 apo C
Liver Transport of
endogenous
liver TAG to
the peripheral
tissues
Type IV
hyperlipoproteinamia
and Diabetes mellitus &
nephrotic syndrome.
Intermediate
density
lipoproteins
UC:
Intermediate
density
E: Broad beta
band
Rich in TAG, apo
B-100 apo E
Liver Transport of
endogenous
liver TAG to
the peripheral
tissues
Type III
hyperlipoproteinamia
and Diabetes mellitus &
neprotic syndrome.
Low density
lipoproteins
UC: Low
density
E: Beta
Position
Rich in
C,CE,PL,apo B-
100 apo E
From VLDL
in Plasma
Cholesterol
influx
Type II
hyperlipoproteinamia
and Diabetes, Neprotic
syndrome.
High density
lipoproteins
UC: High
density
E: Alpha
position
Rich in C,CE and
PL apoA I AII
Liver Cholesterol
efflux
Decreased serum level in
Tangier disease, Diabetes
mellitus

11. APO – LIPO PROTEINS
Apo-
protein
Mol-wt. Site of
production
Componen
t of
Funtions
Apo
A-l
28,000 Intestine HDL-2 Activation of LCAT; ligand for
HDL receptor; anti
atherogenic
Apo
B-100
500,000 Liver LDL, VLDL Binds LDL Receptor
Apo
B-48
250,000 Intestine Chylo-
Microns
48% of B-100
Apo
C-ll
8,900 Liver Chylo; VLDL ACTIVATES LIPO PROTEIN
LIPASE
Apo E 30,000 Liver LDL;VLDL
chylo
Ligand for hepatic uptake
Apo
Lp(a)
Lp(a) Attached to B-100; highly
atherogenic

12. Class : Chylomicrons
• UC: Lowest density E: Remain at origin
• Rich in TAG, apo B-48 apoC.II
• Small Intestine
• Transport of dietary TAG to the peripheral
tissues
• Type I hyperlipoproteinamia and Diabetes
mellitus.
Separation
Composition
Synthesis
Functions
Disorder

13. Class : Very low density
lipoproteins
• UC: Very low density E:Prebeta position
• Rich in TAG, apo B-100 apo C
• Liver
• Transport of endogenous liver TAG to the
peripheral tissues
• Type IV hyperlipoproteinemia and
Separation
Composition
Synthesis
Functions
Disorder

14. Class :Intermediate density lipoproteins
• UC: Intermediate density E: Broad β band
• Rich in TAG, apo B-100 apo E
• Liver
• Transport of endogenous liver TAG to the
peripheral tissues
• Type III hyperlipoproteinamia and
Diabetes mellitus & neprotic syndrome.
Separation
Composition
Synthesis
Functions
Disorder

15. Class : Low density
lipoproteins
• UC: Low density E: Beta Position
• Rich in C,CE,PL,apo B-100 apo E
• From VLDL in Plasma
• Cholesterol influx
• Type II hyperlipoproteinamia and
Diabetes, Neprotic syndrome.
Separation
Composition
Synthesis
Functions
Disorder

16. Class : High density
lipoproteins
• UC: High density E: Alpha position
• Rich in C,CE and PL apoA I AII
• Liver
• Cholesterol efflux
• Decreased serum level in Tangier
disease, Diabetes mellitus
Separation
Composition
Synthesis
Functions
Disorder