Lipid structure, function and chemistry

1
Lipid structure, function and chemistry
Lecture 18
2
Biological Lipids Chemically and Functionally
Diverse

• Soluble in nonpolar solvents
• Hydrocarbon moieties
• Varied roles
• Storage of energy fat
• Membranes
• Pigments
• Hydrophobic carriers
• Biological signals

3
Fatty Acids
4
Fatty Acids
(saturated)
(unsaturated)
5
Some Common Fatty Acids
6
Glycerides

• Fatty acid esters of glycerol

7
(Glycero)Phospholipids
O
O
O
C

CH
O
C
O
O
P
O
OH
Phosphatidic acid
H
Phosphatidylglycerol
CH
OH
OH
Phosphatidylethanolamine
8
More (glycero)Phospholipids
9
Sphingosine
10
Some Typical Sphingolipids

X
O
Sphingomyelin (PC)
P
O
N
O
Glucosylcerebroside
Glucose
Ganglioside
Complex oligosaccharide
11
(glyco) Sphingolipids
12
Lipid Analysis

• Extraction
• Use CCl4/MeOH
• Hydrolysis (saponification)
• Mild alkali ester breakage
• Specific phospholipases

D
C
Analysis TLC, GC-MS, HPLC
13
Sterols
Isoprene unit

• Other sterols
• Ergosterol (fungi)
• Sitosterol (plants)

14
Lipids as Electron Carriers
O
n
O
2H
-2H
O
OH
R
R
O
OH
Plastoquinone
15
Vitamin K and Blood Clotting

• Vitamin K1
• Essential in prothrombin synthesis

16
Carboxyglutamate formation
17
Carotenoid Pigments
?-carotene
18
Lipids in Biosignaling

• Structural variety
• Insolubility
• Protein carriers
• Hydroxylation, etc. solubility
• Location
• Often in membrane
• Action
• Often at membrane surface

19
Some Steroid Hormones
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Metabolism of Vitamin D I
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Metabolism of Vitamin D I
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Metabolism of D3 II
OH
Many steps
HO
OH
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Vitamin A Metabolism
24
Vitamin A Metabolism
25
Vitamin A (Retinal) in Vision
11
12
10
()
C
light
N
H
H
H
()
N
C
H