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Lipids
Lipids
Lipids are natural products more soluble in
nonpolar solvents than in water.
Some of them are related in that they have
acetic acid (acetate) as their biosynthetic origin.
Acetyl coenzyme A serves as the source of
acetate.
Some of them are related in that they have
isoprene as their biosynthetic origin.
Fats, Oils, and Fatty Acids
Fats and Oils
O
O CH2OCR'
RCOCH
CH2OCR"
O
Fats and oils are naturally occurring mixture of
triacylglycerols (also called triglycerides).
Fats are solids; oils are liquids.
Fatty Acids
O
O
O CH2OCR
O
H2O
R'COCH
CH2OCR"
R'COH
CH2OH
HOCR
HOCH
CH2OH
HOCR"
O
O
Acids obtained by the hydrolysis of fats and oils are called
fatty acids.
Fatty acids usually have an unbranched chain with an even
number of carbon atoms.
If double bonds are present, they are almost always cis.
Question
Which one of the following is a triacylglycerol
(triglyceride), a fat?
A)
B)
C)
D)
Question
Which of the following is not an expected
product of the acid hydrolysis of fats?
A)
CH3(CH2)12CO2H
B)
HOCH2CH2(OH)CH2OH
C)
CH3(CH2)16CO2H
D)
CH3(CH2)14CO2H
Fatty Acids
O
OH
H
H
H
H
H
H
H
Systematic name:
H
(5Z, 8Z, 11Z, 14Z)-5,8,11,14Icosatetraenoic acid
Common name: Arachidonic acid
Phospholipids
Waxes
Waxes
Waxes are water-repelling solids that coat the
leaves of plants, etc.
Structurally, waxes are mixtures of esters. The
esters are derived from fatty acids and longchain alcohols.
Waxes
Waxes are water-repelling solids that coat the
leaves of plants, etc.
Structurally, waxes are mixtures of esters. The
esters are derived from fatty acids and longchain alcohols.
O
CH3(CH2)14COCH2(CH2)28CH3
Triacontyl hexadecanoate: occurs in beeswax
Question
When cetyl palmitate is subjected to saponification conditions
(NaOH, H2O, heat) which two compounds will be formed?
A)
CH3(CH2)15OH + HOCH2(CH2)14CH3
B)
CH3(CH2)14CO2Na + NaO2C(CH2)14CH3
C)
CH3(CH2)14CO2H + HOCH2(CH2)14CH3
D)
CH3(CH2)15OH + NaO2C(CH2)14CH3
Prostaglandins
Prostaglandins
Prostaglandins are involved in many biological
processes.
Are biosynthesized from linoleic acid (C18) via
arachidonic acid (C20).
Diterpenes & Pain
Aspirin’s Mode of Action - Prostaglandin Cascades
CO2H
cyclooxygenase
aspirin inhibits enzyme
O
Prostaglandins
OH
COOH
HO
OH
Prostaglandin E2
COOH
HO
OH
Prostaglandin F 1
(Chimes?)
Aspirin Inhibits the Synthesis of
Prostaglandins
(prostaglandin endoperoxide synthase)