INTRODUCTION TO LIPIDS..ppt biochemistry

Introduction
 Definition: water insoluble compounds
 Most lipids are fatty acids or ester of fatty acid
 They are soluble in non-polar solvents such as
petroleum ether, benzene, chloroform
 Functions
 Energy storage
 Structure of cell membranes
 Thermal blanket and cushion
 Precursors of hormones (steroids and prostaglandins)
 Types:
 Fatty acids
 Neutral lipids
 Phospholipids and other lipids

Classification:
Saponifiable—can be
hydrolyzed by NaOH to make soap
Non-saponifiable—cannot be
hydrolyzed, includes sterols such as
cholesterol
Saponifiable lipids are further
subdivided:
Simple- made of fatty acids
plus alcohol
Compound- either phospho- or
glycolipids, which contain
phosphate or sugar groups as well
as fatty acids

Lipids are non-polar (hydrophobic) compounds, soluble in organic
solvents.
Most membrane lipids are amphipathic, having a non-polar end and a
polar end.
Fatty acids consist of a hydrocarbon chain with a carboxylic acid at one
end.
A 16-C fatty acid: CH3(CH2)14-COO
-
Non-polar polar
A 16-C fatty acid with one cis double bond between C atoms 9-10 may be
represented as 16:1 cis 9
.

Some fatty acids and their common names:
14:0 myristic acid; 16:0 palmitic acid; 18:0 stearic
acid; 18:1 cis9
oleic acid
18:2 cis9,12
linoleic acid
18:3 cis9,12,15
-linonenic acid
20:4 cis5,8,11,14
arachidonic acid
20:5 cis5,8,11,14,17
eicosapentaenoic acid (an omega-3)
Double bonds in fatty acids
usually have the cis
configuration.
Most naturally occurring fatty
acids have an even number
of carbon atoms.
C
O
O
1
2
3
4



fatty acid with a cis-9
double bond

There is free rotation about C-C bonds in the fatty acid
hydrocarbon, except where there is a double bond.
Each cis double bond causes a kink in the chain.
Rotation about other C-C bonds would permit a more
linear structure than shown, but there would be a kink.
C
O
O
1
2
3
4



fatty acid with a cis-9
double bond

Fats & Oils
Simplest lipids, called triacylglycerols
or simply triglycerides. Main form of
fat storage in plants, animals, and
man. Males store 21% fat on
average, females 26%.

Essential Fatty
Acids
Fatty acids which cannot be made by the body, but
are important for health and growth are called
essential.
Linolenic acid, found mostly in vegetable oils, is an
important reducer of LDL (low density
lipoproteins), which help to take cholesterol into
the blood and cause atherosclerosis (buildup of
plaque in the blood vessels) a prime cause of heart
attacks
Arachidonic acid is important in making eicosanoids,
molecules which regulate and protect the body
from invasion by microorganisms.

Simple Lipids—Fatty Acids
Simple triglycerides contain the same
fatty acid in all three positions; mixed
triglycerides contain two or three
different fatty acids
Fatty acids are carboxylic acids with
from 4 to 20 carbons in the chain. The
chain can be saturated (only single
bonds) or unsaturated (one or more
double bonds in the chain), Saturated
are usually solid at room temperature,
unsaturated are usually liquid

Less common fatty acids
 iso – isobutyric acid
 anteiso
 odd carbon fatty acid – propionic acid
 hydroxy fatty acids – ricinoleic acid,
dihydroxystearic acid, cerebronic acid
 cyclic fatty acids – hydnocarpic,
chaulmoogric acid
R
H3C
H3C H3C
R
CH3
(CH2)12-CO2H (CH2)10-CO2H
chaulmoogric acid hydnocarpic acid

H3C
CH3 CH3 CH3 CH3
COOH
PHYTANIC ACID
A plant derived fatty acid with 16 carbons and branches at C 3, C7, C11 and
C15. Present in dairy products and ruminant fats.
A peroxisome responsible for the metabolism of phytanic acid is defective
in some individuals. This leads to a disease called Refsum’s disease
Refsum’s disease is characterized by peripheral polyneuropathy, cerebellar
ataxia and retinitis pigmentosa

(CH2)10
H3C C C (CH2)4 COOH
TARIRIC ACID
CH
H2C (CH2)4 C C C C (CH2)7 COOH
ERYTHROGENIC ACID
Less common fatty acids
These are alkyne fatty acids

Unsaturated fatty acids
 number and position of the double
bond(s)Various conventions are in use for
indicating the
H
C CH(CH2)7COOH
(CH2)7
H3C
1
9
18
10
18:1,9 or 9
18:1
H3C CH2CH2CH2CH2CH2CH2CH2CH CH(CH2)7COOH
1
9
10
17
n
2 3 4 5 6 7 8 9 10 18

9, C18:1 or n-9, 18:1

 Monoenoic acids (one double bond):
 16:1, 9 7: palmitoleic acid (cis-9-
hexadecenoic acid
 18:1, 9 9: oleic acid (cis-9-octadecenoic acid)
 18:1, 9 9: elaidic acid (trans-9-octadecenoic
acid)
 22:1, 13 9: erucic acid (cis-13-docosenoic
acid)
 24:1, 15 9: nervonic acid (cis-15-
tetracosenoic acid)

 Trienoic acids (3 double bonds)
 18:3;6,9,12 6 : -linolenic acid (all cis-6,9,12-
octadecatrienoic acid)
 18:3; 9,12,15 3 : -linolenic acid (all-cis-
9,12,15-octadecatrienoic acid)
 Tetraenoic acids (4 double bonds)
 20:4; 5,8,11,14 6: arachidonic acid (all-cis-
5,8,11,14-eicosatetraenoic acid)

 Pentaenoic acid (5 double bonds)
 20:5; 5,8,11,14,17 3: timnodonic acid or
EPA (all-cis-5,8,11,14,17-eicosapentaenoic
acid)*
 Hexaenoic acid (6 double bonds)
 22:6; 4,7,10,13,16,19 3: cervonic acid or
DHA (all-cis-4,7,10,13,16,19-
docosahexaenoic acid)*
Both FAs are found in cold water fish oils

Waxes
Waxes are simple lipids which are esters of long
chain alcohols and fatty acids. Beeswax is a 30
C alcohol connected to a 16 C fatty acid
Waxes are completely water resistant and make
the coatings on leaves, skin, feathers, fur, and
fruit. They can be used on floors and furniture
for the same protecting quality.

4. Membrane lipids
1) phospholipids
- phosphoglyceride: phosphatidyl serine (ethanolamine,
choline, inositol)
- sphingolipid: spingosine → sphingomyelin
2) glycolipids
- sugar-containing lipids
- cerebrosides
- gangliosides
3) cholesterol

CH2
CH
CH2
OH
O
H
O
H
C
R3
CH2
CH
H2C
OH
O
O
C
R1
C
R2
O
O
O
CH2 O
C
C
H O
C
O
R2
C
H2 O
C
O
R3
R1
O
GLYCEROL
TRI ACYL GLYCEROL ( TRIGLYCERIDE)
Triacyl glycerol
BIOLOGICAL MEMBRANES

O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
OH
OH
Glycerol phospholipids
O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
O
OH
CH2
CH2
NH2
O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
O
OH
CH2
CH2
N
+
CH3
C
H3
CH3

O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
O
OH
CH2
C
H
NH2
COOH
O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
OH CH
CH
CH
CH
CH
CH
O
O
H
OH
O
H
OH
OH
O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
O
OH
C
H
C
H
CH2
OH
HO
OH
O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
O
OH
C
H
C
H
CH2
OH
OH
O
R
CH2
CH
CH2
O
O
O
O
R
P
O
O
O
H
Phosphotidyl serine
Phosphotidyl Inositol
Phosphatidyl glycerol
Diphosphatidylglycerol (cardiolipin)

H2C C
H
H2
C
O
O
O
O
O
P
O
OH
O
H2
C
H2
C NH2
H2C C
H
H2
C
O
O
O
O
O
P
O
OH
O
H2
C
H2
C N CH3
CH3
CH3
H2C C
H
H2
C
O
O
O
O
O
P
O
OH
O
HO OH
OH
OH
HO
H2C C
H
H2
C
O
O
O
O
P
O
OH
NH2
CH C
H2
C
OH
O
O
Phosphotidyl Ethanolamine
Phosphotidyl Choline
Phosphotidyl Inositol
Phosphotidyl Serine

H2C C
H
H2
C
O
O
R
R
O
O
O
P
O
OH
O
CH2
CH
H2
C
O
O
R
R
O
O
O
P
O
OH
H
C C
H
H2
C OH
OH
OH
H2C C
H
H2
C
O
O
R
R
O
O
O
P
O
OH
O
H
C C
H
H2
C O
OH
OH
Phosphotidyl Glycerol
Diphosphotidyl Glycerol

Ether
glycerophospholipids
 Possess an ether linkage instead of an
acyl group at the C-1 position of
glycerol
 PAF ( platelet activating factor)
 A potent mediator in inflammation, allergic
response and in shock (also responsible for
asthma-like symptom
 The ether linkage is stable in either acid or base
 Plasmalogens: cis ,-unsaturated ethers
 The alpha/beta unsaturated ether can be hydrolyzed more
easily

Ether
glycerophospholipids
H2C CH
O
CH2
O
O
P
O
-
O O
C O
CH3
CH2 CH2 N
CH3
CH3
CH3
platelet activating factor or PAF
H2C CH
O
CH2
O
O
P
O
-O O
C O
CH2 CH2 N
CH3
CH3
CH3
A choline plasmalogen
H
H

O
R
CH2
C
H
CH2
O
O
O
O
R
P
O
O
OH
X
Phospholipase A1
Phospholipase A2
Phospholipase C
Phospholipase D
O
PALMITIC
CH2
C
H
CH2
O
O
O
O
PALMITIC
P
O
O
OH
CH2
CH2
N
+
CH3
C
H3
CH3
SURFACTANT ( DIPALMITOYL PHOSPHATIDYL CHOLINE

CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH
CH
CH
CH
CH2
OH
NH2
OH
CH2
C
H3
C
H3
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
C
O
O
H
C
H3
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
C
O
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH2
CH
CH
CH
CH
CH2
OH
NH
OH
CH2
C
H3
Sphingosine
Palmitic acid
+
Ceramide
R
1 CH2
CH2
CH2
C
NH
R
CH
CH
CH
C
H
CH2
O
OH
OH
Ceramide
Acylated Sphingosine
SPHINGOLIPIDS
R
1
CH2
CH2
CH2
C
NH
R
CH
CH
CH
C
H
CH2
O
OH
O
P
O
OH
O
CH2
CH2
N
+
CH3
CH3
CH3
Hydrophilic end
Hydrophobic end
CERAMIDE
SPHINGOMYELIN
OH
NH2
OH
O
O
H
O
OH
NH
OH
Sphingosine
Palmitic acid
+
Ceramide
R
1
NH
R
O
OH
OH
Ceramide
SPHINGOLIPIDS

OH
NH2
OH
O
O
H
O
OH
NH
OH
Sphingosine
Palmitic acid
+
Ceramide
R
1
R
O
OH
OH
Ceramide
SPHINGOLIPIDS

SPHINGOLIPIDS
OH
CH2
HC
CH
CH
CH
(CH2)12
NH
C
H3
O
C
R
C
H3
O
CH2
O
H
O
OH OH
OH
OH
CH2
CH
CH
CH
CH
(CH2)12
NH
C
H3
O
C
R
C
H3
O
CH2
O
H
O
OH OH
OH
Galactocerebroside
Glucocerebroside
OH
CH2
CH
CH
CH
CH
(CH2)12
NH
C
H3
O
C
R
C
H3
O
CH2
O
H
O
OH OH
O
CH2
O
H
O
OH OH
OH
Lactosyl ceramide
O
CH2
O
H
O
OH OH
OH
OH
CH2
CH
CH
CH
CH
(CH2)12
NH
C
H3
CH2
C
R
C
H3
O
CH2
O
H
O
OH OH
O
CH2
O
H
O
OH OH
Trihexosyl ceramide
CEREBROSIDES
R OH
N
H
O
H
R
1
O

R
1
CH2
CH2
CH2
C
NH
R
CH
CH
CH
C
H
CH2
O
OH
O
O
H OH
H
H
O
H
H
OSO3H
H
O
H
Some Galactocerebrosides are sulfated at
position 3 of the galactose

(CH2)12
R NH
O H2
C
O
OH
O
O
O
O
O
OH
CH2
HO
OH
O
CH2
HO
CH2
HO
OH
O
OH
NH
HO HO
OH
H2
C
HO
Cer
Glc
Gal
GalNAc
C
O
CH3 Gal
O
NANA
Cer Glc Gal GalNAc Gal
GM1
GM2
GM3
NANA
GANGLIOSIDES

O
O
O
H
OH
OH
O
O
O
O
H
OH
OH
OH
O
O
H
OH
OH OH
N
H
O
OH
O
O
H
OH
NH
O
O
O
H
OH
OH
O
O
O
O
H
OH
OH
OH
O
O
OH
OH OH
N
H
O
O
Globoside Gb3
Globoside Gb4

Blood Group A
Blood Group B
Blood Group O
Fuc(a1-2)
Gal(B1-4)
GalNAc(a1-3)
GalNAc(B) O Cer
Fuc(a1-2)
Gal(B1-4)
Gal(a1-3)
GalNAc(B) O Cer
Fuc(a1-2)
Gal(B1-4)GalNAc(B) O Cer
THE UNIVERSAL BLOOD GROUP ANTIGENS ARE
SPHINGOLIPIDS WHICH ARE EXPRESSED ON THE SURFACE
OF ERYTHROCYTES

13
14
9
8
10
17
12
11
15
16
7
5
6
18
19
1
4
2
3
H
H
H
HO
CH CH2 CH2 CH2
CH3
HC
CH3
CH3
21
20 22 23 24 25
26
27
Polar Head Non polar Head
CHOLESTEROL

Cholesterol is largely
hydrophobic.
But it has one polar
group, a hydroxyl,
making it
amphipathic.
Cholesterol
HO
Cholesterol, an
important constituent of cell
membranes, has a rigid ring
system and a short
branched hydrocarbon tail.
cholesterol
PDB 1N83

Cholesterol
in membrane
Cholesterol inserts into bilayer membranes with
its hydroxyl group oriented toward the aqueous
phase & its hydrophobic ring system
adjacent to fatty acid chains of phospholipids.
The OH group of cholesterol forms hydrogen
bonds with polar phospholipid head groups.
Cholesterol
HO

But the presence of cholesterol in a phospholipid membrane interferes
with close packing of fatty acid tails in the crystalline state, and thus
inhibits transition to the crystal state.
Phospholipid membranes with a high concentration of cholesterol have a
fluidity intermediate between the liquid crystal and crystal states.
Cholesterol
in membrane
Interaction with the relatively rigid cholesterol
decreases the mobility of hydrocarbon tails of
phospholipids.

Peripheral proteins are on the membrane surface.
They are water-soluble, with mostly hydrophilic
surfaces.
Often peripheral proteins can be dislodged by
conditions that disrupt ionic & H-bond interactions,
e.g., extraction with solutions containing high
concentrations of salts, change of pH, and/or
chelators that bind divalent cations.
Membrane proteins
may be classified as:
 peripheral
 integral
 having a lipid
anchor
integral
lipid
anchor
peripheral
lipid bilayer
Membrane
Proteins

Integral proteins have domains that extend into
the hydrocarbon core of the membrane.
Often they span the bilayer.
Intramembrane domains have largely hydrophobic
surfaces, that interact with membrane lipids.
integral
lipid
anchor
peripheral
lipid bilayer
Membrane
Proteins

Some proteins bind to membranes via a covalently
attached lipid anchor, that inserts into the bilayer.
A protein may link to the cytosolic surface of the plasma
membrane via a covalently attached fatty acid (e.g.,
palmitate or myristate) or an isoprenoid group.
Palmitate is usually attached via an ester linkage to the
thiol of a cysteine residue.
A protein may be released from plasma membrane to
cytosol via depalmitoylation, hydrolysis of the ester link.
lipid
anchor
membrane
H3C (CH2)14 C
O
S CH2 CH
C
NH
O
palmitate
cysteine
residue

An isoprenoid such as a farnesyl
residue, is attached to some
proteins via a thioether linkage to
a cysteine thiol.
C H C H 2
C
H 3 C
C H 3
C H C H 2
C
C H 2
C H 3
C H C H 2 S P r o t e in
C
C H 2
C H 3
f a r n e s y l r e s i d u e l i n k e d t o p r o t e i n v i a c y s t e i n e S
lipid
anchor
membrane

Glycosylphosphatidylinositols (GPI) are complex
glycolipids that attach some proteins to the outer
surface of the plasma membrane.
The linkage is similar to the following, although the
oligosaccharide composition may vary:
protein (C-term.) - phosphoethanolamine – mannose -
mannose - mannose - N-acetylglucosamine – inositol (of PI
in membrane)
The protein is tethered some distance out from the
membrane surface by the long oligosaccharide
chain.
GPI-linked proteins may be released from the outer
cell surface by phospholipases.

Lipid storage diseases
 also known as sphingolipidoses
 genetically acquired
 due to the deficiency or absence of a catabolic
enzyme
 examples:
 Tay Sachs disease
 Gaucher’s disease
 Niemann-Pick disease
 Fabry’s disease
 http://www.ninds.nih.gov/disorders/lipid_storage_di
seases/lipid_storage_diseases.htm

What are Lipid Storage Diseases?
Lipid storage diseases are a group of inherited metabolic
disorders in which harmful amounts of fatty materials (called
lipids) accumulate in some of the body’s cells and tissues. Over
time, this excessive storage of fats can cause permanent
cellular and tissue damage, particularly in the brain, peripheral
nervous system, liver, spleen, and bone marrow. Lipid storage
diseases are inherited from one or both parents who carry a
defective gene. Symptoms may appear early in life or develop
in the teen or even adult years. Neurological complications of
the lipid storage diseases may include ataxia, eye paralysis,
brain degeneration, seizures, learning problems, spasticity,
feeding and swallowing difficulties, slurred speech, loss of
muscle tone, hypersensitivity to touch, burning pain in the
arms and legs, and clouding of the cornea

Genetic defects in
ganglioside metabolism
 leads to a buildup of gangliosides
(ganglioside GM2) in nerve cells, killing
them
NAc
Gal Gal Gal Glu
NAcNeu
enzyme that hydrolyzes here (beta hexosaminodase)
is absent in Tay-Sachs disease
CER

Tay-Sachs disease
 a fatal disease which is due to the
deficiency of hexosaminidase A activity
 accumulation of ganglioside GM2 in the
brain of infants
 mental retardation, blindness, inability to
swallow
 a “cherry red “ spot develops on the
macula (back of the the eyes)
 Tay-Sachs children usually die by age 5
and often sooner

Genetic defects in
globoside metabolism
 Fabry’s disease:
 Accumulation of ceramide trihexoside in
kidneys of patients who are deficient in
lysosomal -galactosidase A sometimes
referred to as ceramide trihexosidase
 Skin rash, kidney failure, pains in the lower
extremities
 Now treated with enzyme replacement
therapy: agalsidase beta (Fabrazyme)

Genetic defects in
cerebroside metabolism
 Krabbe’s disease:
 Also known as globoid leukodystrophy
 Increased amount of galactocerebroside in the white matter
of the brain
 Caused by a deficiency in the lysosomal enzyme
galactocerebrosidase
 Gaucher’s disease:
 Caused by a deficiency of lysosomal glucocerebrosidase
 Increase content of glucocerebroside in the spleen and liver
 Erosion of long bones and pelvis
 Enzyme replacement therapy is available for the Type I
disease (Imiglucerase or Cerezyme)
 Also miglustat (Zavesca) – an oral drug which inhibits the
enzyme glucosylceramide synthase, an essential enzyme for
the synthesis of most glycosphingolipids

Genetic defects in
ganglioside metabolism
 Metachromatic leukodystrophy
 accumulation of sulfogalactocerebroside (sulfatide) in
the central nervous system of patient having a
deficiency of a specific sulfatase
 mental retardation, nerves stain yellowish-brown with
cresyl violet dye (metachromasia)
 Generalized gangliosidosis
 accumulation of ganglioside GM1
 deficiency of GM1 ganglioside: -galactosidase
 mental retardation, liver enlargement, skeletal
involvement

Niemann-Pick disease
 principal storage substance:
sphingomyelin which accumulates in
reticuloendothelial cells
 enzyme deficiency: sphingomyelinase
 liver and spleen enlargement, mental
retardation

Prostaglandins and other
eicosanoids
(prostanoids)
 local hormones, unstable, key
mediators of inflammation
 derivatives of prostanoic acid
COOH
20
8
12
prostanoic acid
9
11
15

O R
O
O
O
P
O
O
O-
X
O
COOH
CH3
phospholipase A 2 (enzyme that hydrolyzes
at the sn-2 position - inhibited
indirectly by corticosteroids)
H20
prostaglandin synthase
(also known as cyclooxygenase)
O
O
COOH
OH
very unstable
bond
PGH2
COX is inhibibited by
aspirin and other NSAIDs

O
O
COOH
OH
PGH2
COOH
OH
O
HO
COOH
OH
HO
HO
PGE2 PGF2
key mediator of inflammation

O
R1
R2
O
R1
R2
PGA PGB
O
R1
R2
PGC
R1
R2
HO
O
PGD
R1
R2
O
HO
R1
R2
HO
HO
R1
R2
O
O
PGE PGFa PGG and PGH
R2
HO
O
R1
R1
R2
O
PGJ
R1
R2
O
O
PGK
PGI
O
O
R1
R2 O
R1
R2
HO
OH
TXA TXB
SUBSTITUTION PATTERN OF PROSTANOIDS

Prostacyclins,
thromboxanes and
leukotrienes
 PGH2 in platelets is converted to
thromboxane A2 (TXA2) a vasoconstrictor
which also promotes platelet aggregation
 PGH2 in vascular endothelial cells is
converted to PGI2, a vasodilator which
inhibits platelet aggregation
 Aspirin’s irreversible inhibition of platelet
COX leads to its anticoagulant effect

Functions of eicosanoids
 Prostaglandins – particularly PGE1 – block
gastric production and thus are gastric
protection agents
 Misoprostol (Cytotec) is a stable PGE1
analog that is used to prevent ulceration
by long term NSAID treatment
 PGE1 also has vasodilator effects
 Alprostadil (PGE1) – used to treat infants with
congenital heart defects
 Also used in impotance (Muse)

Functions of eicosanoids
 PGF2 – causes constriction of the
uterus
 Carboprost; “Hebamate” (15-Me-PGF2) –
induces abortions
 PGE2 is applied locally to help induce
labor at term

C5H11
COOH
O
LEUKOTRIENEA 4 (LTA 4)
C5H11
HO
COOH
OH
LEKOTRIENE B 4 (LTB 4)
Non-peptidoleuktrienes: LTA4 is formed by dehydration of
5-HPETE, and LTB4 by hydrolysis of the epoxide of LTA4
Leukotrienes

Biological activities of
leukotrienes
1. LTB4 - potent chemoattractent
- mediator of hyperalgesia
- growth factor for keratinocytes
2. LTC4 - constricts lung smooth muscle
- promotes capillary leakage
1000 X histamine
3. LTD4 - constricts smooth muscle; lung
- airway hyperactivity
- vasoconstriction
4. LTE4 - 1000 x less potent than LTD4
(except in asthmatics)

C5H11
H S
Cys
gGlu
OH
COOH
LEUKOTRIENE F4 (LTF4)
C5H11
H S
Cys
OH
COOH
Gly
gGlu
LEUKOTRIENE C4 (LTC4)
Leukotrienes are derived from arachidonic acid via the enzyme
5-lipoxygenase which converts arachidonic acid to 5-HPETE
(5-hydroperoxyeicosatetranoic acid) and subsequently by
dehydration to LTA4
peptidoleukotrienes
Leukotrienes

C5H11
H S
Cys
OH
COOH
LEUKOTRIENE E 4 (LTE4)
C5H11
H S
Cys
OH
COOH
Gly
LEUKOTRIENE D 4 (LTD4)
Leukotrienes are synthesized in neutrophils, monocytes, macrophages,
mast cells and keratinocytes. Also in lung, spleen, brain and heart.
A mixture of LTC4, LTD4 and LTE4 was previously known as the
slow-reacting substance of anaphylaxis
peptidoleukotrienes
Leukotrienes

INTRODUCTION TO LIPIDS..ppt biochemistry

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