2. 2
Phospholipids
Phospholipids are compound lipids and are of
two types
Glycerophospholipids and
sphingophospholipids The
Glycerophospholipids contain glycerol,
saturated and unsaturated fatty acid,
phosphoric acid and a nitrogenous base.
The various glycerophospholipids are
phosphatidyl choline (lecithin)
Phosphatidyl serine( cephalin)
Phosphatidyl ethanolamine
Phosphatidyl inositol
Cardiolipin and plasmalogen
3. Sphingophospholipids contains sphingosine
(instead of glycerol) fatty acid, phosphate and
choline
Ex: sphingomyelin
CH2-O-CO-R1 CH2-O-CO-R1
CH-O-CO-R2 CH-O-CO-R2
CH2-O-phosphoric acid CH2-O-phosphoric acid-Choline
phosphatidic acid Lecithin (phosphatidyl choline)
phosphatidyl choline (lecithin)
Contains alcohol, fatty acid, phosphoric acid and
choline.
The fatty acid part of R1 is saturated fatty acid and
R2 at
β position is an unsaturated fatty acid.
3
4. Lecithin is present in brain, nervous tissue, sperm
and egg yolk.
Lecithins is a surface-active agents and help in
emulsification of fats.
Dipalmitoyl lecithin is a lung surfactant (lowers
surface tension) prevents the collapse of lung
alveoli.
Absence of dipalmitoyl lecithin in premature
infants may produce respiratory distress syndrome
or hyaline membrane disease.
4
5. Phosphatidyl serine (cephalin)
Contains alcohol, fatty acid, phosphoric acid and serine as a
nitrogenous base instead of choline present in
lecithin.
Cephalins are present in brain, erythrocytes and many other
tissues.
Phosphatidyl inositol
Contains phosphatidic acid bound to the alcohol inositol
instead
of a nitrogenous base.
Important component of cell membrane.
The action of certain hormones (e.g. oxytocin, vasopressin) is
mediated through phosphatidyl inositol (PI).
In response to hormonal action, PI is cleaved to diacyl glycerol
(DAG) and inositol triphosphate (IP3).
Both these compounds act as second messenger for
hormonal action.
5
6. Phosphatidyl ethanolamine
Contains alcohol, fatty acid, phosphoric acid and
Ethanolamine as a nitrogenous base
Plasmalogen (Phospho Lipid)
They differ from lecithin or cephalin in α1 position of
glycerol where the fatty acid is replaced by a long chain
unsaturated aliphatic aldehyde such as palmitic or stearic
aldehyde
Present in large quantities in the skeletal muscle, cardiac
muscle
and in semen.
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7. Cardiolipin Or Phosphatidyl Glycerol.
It is diphosphatidyl glycerol.
It contains two molecules of phosphatidic acid
held by glycerol.
Present in the inner mitochondrial membrane and
Myocardium and has antigenic properties.
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8. Sphingomyelin
This is a Sphingophospholipid OR PhosphoSphingosides.
It contains unsaturated amino alcohol (sphingosine)
(instead of glycerol).
Common one is Sphingomyelin.
They contain a molecule of choline, phosphoric acid and
fatty acid.
Sphingomyelin makes up a large part of the myelin sheath.
Also present in brain, lungs, nerve, bile , amniotic fluid and
other tissues.
Ceramide
Sphingosine+fatty acid
It is formed by the esterification sphingosine (an amino
alcohol) with a fatty acid of high molecular weight.
Principally found in white matter of brain in myelin sheath
and medullated nerves.
It is common for all glycolipid and sphingomyelin.
8
9. Deposition of sphingomyelin in liver, lymph
nodes, bone marrow and central nervous
system results in Neimman-Pick disease.
It may be due to the deficiency of
sphingomyelinase enzyme in these tissues.
9
Dr. S. NayakDr. S. Nayak
10. GLYCOLIPIDS
CARBOHYDRATE AND CERAMIDE(SPHINGOSINE+FATTY ACID)
NON PHOSPHORYLATED LIPIDS
1. CEREBROSIDE OR GLYCOSPHINGOSIDE OR CERAMIDE
MONOHEXOSIDE
Nervous tissue,white matter,myelin sheath
Ceramide + glucose – glucocerebroside
Ceramide + galactose – galactocerebroside
Hydrolysis yield sugar , high MW FA, sphingosine
Types GAUCHERS DISEASE
2. GLOBOSIDES OR CERAMIDE OLIGOSACCHARIDE or GANGLIOSIDE
Two or more hexose or hexoseamine attached to ceramide
Ceramide + glucose + galactose = lactosyl ceramide
Present in erythrocyte membrane
13. Abundant in brain and nerve tissues
Found in egg yolk, what germ, yeast
13
C
O
(CH2)14CH3
+
choline, an amino alcohol
O C
O
(CH2)14CH3
CH O
CH2 O P
O
O-
O CH2CH2N(CH3)3
CH2
