1. Triacylglycerol Synthesis
Fatty acyl-CoA
DHAP reduction to glycerol-PO or
Glycerol kinase to glycerol-PO4
Two esterifications
Diacylglycerol-PO4 intermediate
Triacylglycerol
O-C-R O
R-C-O

2. Triacylglycerol Biosynthesis
glycolysis
CH2OH
CH2OP
C=O
NADH + NAD+
CH2OH
HO-C-H
CH2OP
ADP ATP
CH2OH
HO-C-H
glycerol kinase
glycerol-PO4
dehydrogenase
Not in adipose
tissue
DHAP
Glycerol-PO4
R-C~CoA O 2
CH2O-C-R
R-C-O-C-H
CH2OP O
Phosphatidic
acid
R-C~CoA O
H2O
PO4
CH2O-C-R
R-C-O-C-H
CH2OH O
CH2O-C-R
R-C-O-C-H O
Phospholipid
biosynthesis
1,2 Diacylglycerol
(DAG)

3. Question
Can a triacylglycerol (triglyceride) storage fat be synthesized entirely from glucose, i.e., every carbon in the fat comes from a sugar?
Answer: YES

4. Glycerophospholipids
CH2O-C-R
R-C-O-C-H
CH2OP O
Phosphatidic
Acid
Phospholipid
Biosynthesis
(smooth ER)
- or + O
Ester linkage
Polar component
- or +
= choline, serine, ethanolamine, etc
Glycerophospholipids O
CH2O-C-R
R-C-O-C-H
CH2OPO-CH2CH2-N(CH3)3 +
Phosphatidylcholine or lecithin

5. Strategy of Glycerophospholipid Biosynthesis
Activate diacylglycerol
Activate appending moiety (salvage)
Ribose
PPP-
CTP

6. Bacteria (Prokaryotes)
Activate Phosphatidic acid
Phosphatidic acid + CTP
CDP-diacylglycerol
+ PPi
CH2O-C-R
R-C-O-C-H
CH2OP~P-ribose-Cytosine O
(CDP-diacylglycerol)

7. Bacteria (Prokaryotes)
CDP-diacylglycerol
Serine
CMP
Glycerol-PO4
CMP
Phosphatidylserine
Phosphatidylglycerol-3-PO4
Phosphatidyl-
glycerol
CO2
glycerol
Phosphatidylethanolamine
Cardiolipin
Most prominent membrane lipid in bacteria
Wassermann antigen for diagnosing
syphilis

8. Eukaryotes 1 Glycerol 2 Glycerol-3-PO4 DHAP CH2O-C-R R-C-O-C-H CH2OP O
ATP
Glycerol 2
Glycerol-3-PO4
DHAP
FA-CoA
CH2O-C-R
R-C-O-C-H
CH2OP O
1-Acyl-DHAP
Phosphatidic acid
NADPH 3
DAG
1-Acyl-glycerol-3-PO4
ATP
CTP
CDP-diacylglycerol Pi
ethanolamine (CDP-ethanolamine)
CH2O-C-R
R-C-O-C-H
CH2OH O
choline (CDP-choline)
Serine (phosphatidylethanolamine)
Glycerol (CDP-diacylglycerol)
Inositol (CDP-diacylglycerol)
1,2 DAG
Cardiolipin (phosphatidylglycerol)

9. N H N O O O N N C H C H O P O P O C H O O O H O C y t i d i n e d i p2 N O O O N + H N C H C H O P O P O C H 2 2 3 2 O O O
ethanolamine H O C y t i d i n e d i p h o s p h a t e ( C D P ) O H

10. SALVAGE Ethanolamine or choline HO-CH2-CH2-NH3+ ATP ADP
Ethanolamine kinase or
choline kinase
O-CH2-CH2-NH3+
HO-P- O O-
CTP
PPi
Phosphoethanolamine
-P-
O-CH2-CH2-NH3+
O-P- O O-
Cytidine-
DAG
CMP
CDP-ethanolamine
Phosphatidylethanolamine
Phosphatidylserine
Serine
Ethanolamine