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Chapter 19
Lipids (类脂)
Ref: Wade, chapter 25
Lipids are compounds that can be extracted from
cells and tissues by nonpolar organic solvents.
Waxes: 蜡
Complex lipids
Fats and oils 油脂: glycerides
phospholipides: 磷脂
Steriods 甾体
Simple lipids
Terpenes 萜
Prostaglandins 前列腺素
19-1 Waxes
Most waxes are esters of long-chain fatty acids and
long-chain alcohols.
Waxes are found as protective coatings on the skin, fur, or
feathers of animals, and on the leaves and fruits of plants.
O
CH3(CH2)15
O C
(CH2)14CH3
spermaceti
鲸蜡
O
CH3(CH2)29
O C
(CH2)24CH3
beeswax
蜂蜡的一种
Notice: parafin wax (石蜡) is a mixture of alkanes
with high molecular weight。
19-2 Triglycerides 三酸甘油酯 （25-3, 4）
Oils: Triacylglycerols that are liquids at room temperature.
Fats: Triacylglycerols that are solids at room temperature.
O
H2C O C R
O
H2C OH
(1) OH- / H2O, heat
HC O C R'
HC OH +
+
(2) H3O
O
RCOOH
R'COOH
H2C O C R''
H2C OH
R''COOH
A fat or oil
(ÓÍ»òÖ¬£©
Glycerol
( ±ûÈý´¼)
Fatty acids
(Ö¬·¾Ëᣩ
The primary function of triacylglycerols in animal is as an
energy reserve.
Common naturally occurring fatty acids
月桂酸
肉豆蔻酸
软脂酸
硬脂酸
花生酸
棕榈油酸
油酸
亚油酸
亚麻酸
花生四烯酸
A fat
An oil
① Most of fatty acids have unbrached chains and they have
an even number of carbon atoms.
② The double bonds in unsaturated fatty acids are all cis
and not conjugated..
③ Saturated fatty acids have relatively high melting points
and unsaturated fatty acids have relatively low points.
Saponification reaction: soaps
Synthetic detergents
CH3(CH2)nCH2SO2O-Na+
Sodium alkanesulonates
(Íé»ù»ÇËáÄÆÑΣ©
CH3(CH2)nCH2OSO2O-Na+
Sodium alkyl sulfates
(Íé»ùÁòËáÄÆÑΣ©
CH3
+Na-OO S
2
CH(CH2)nCH2CH3
Sodium alkylbenzenesulfonates
(Íé»ù±½»ÇËáÄÆÑΣ©
Synthesis of detergents offer an advantage over soaps; they
function well in “hard” water.
19-3 Phospholipids 磷脂 （25-5）
CH2OCOR
a phosphatidic acid
磷脂酸
From fatty acid
CHOCOR'
O
CH2 O P OH
OH
O
From phosphoric acid
O
H2C O C R
O
H2C O C R
O
HC O C R'
O
HC O C R'
O
H2C O P OCH2CH2N+(CH3)3
OLecithins
(ÂÑÁ×Ö¬)
hydrophobic portion
H2C O P OCH2CH2NH3+
Ohydrophilic
Cephalins
(ÄÔÁ×Ö¬)
portion
Phosphoacylglycerols form membranes by arranging
themselves into a lipid bilayer
19-4 Terpenes 萜类
• Terpenes contain carbon atoms in multiples of five
• They are made by joining together 5-carbon isoprene
units
The Isoprene Rule
异戊二烯规则
Classification of terpenes
单萜
倍半萜
双萜
三萜
四萜
OH
OH
Limonene
(ÄûÃÊÓ;«)
 -Pinene
(ËÉÝÆ
)
Geraniol
(Ïã Ò¶´¼)
monoterpenes
Menthol
(±¡ ºÉ´¼)
triterpenes
squalene 角鲨烯
Lycopene (番茄红素)
-carotene（胡萝卜素）
tetraterpenes
OH
2
Vitamin A
The biosynthesis of terpenes:
CO2
CH3COSCoA
HOOCCH2COSCoA
丙二酰辅酶A
（活化的乙酸）
乙酰辅酶A
CH3COCH2COSCoA
CH3COSCoA
H3C
H3C
H3C
hydrolysis
-CO2, -CoASH
OH
C
乙酰乙酰辅酶A
reduction
CH3COSCoA
OH
C
CH2CH2OH
HOOCH2C
3,5-dihydroxy-3-methylpentanoic acid
CH2COSCoA
H3C
C
HOOCH2C
OH
ATP
CH2CH2OH
-CO2
H3C
C
H2C
CH2CH2OPP
H3C
H3C
enzyme
C
C
H3C
H3C
C
H
C
H2C
C
H
CH2
CH2OPP
H3C
C
C
CH2 CH2
H3C
H
H2O
H3C
H3C
C
H
C
CH2OH
H3C
C
CH2 CH2
C
H
CH2CH2OPP
OPP焦磷酸酯
19-5 Steroids (甾体)
18
CH317
12
19
1
2
A
3
11
C
CH3
10
9
4
8
7
6
D
14
B
5
16
13
15
The A and B rings are also trans fused in most naturally
occurring steroids
Substituents on the same side of the steroid ring
system as the angular methyl groups are substituents
Those on the opposite side of the plane of the ring
system are a-substituents
H
H3C
H 3C
CH3
H
HO
C
H
H
H
H
Cholesterol 胆固醇
Cholesterol is known to serve as an intermediate in the biosynthesis
of all of the steroids of the body.
Biosynthesis of Cholesterol
角鲨烯
（三萜）
羊毛甾醇
（三萜）
胆固醇
conrotatory
顺旋
7-脱氢胆甾醇
[1,7] σ-迁移
O
OH
H3C
H3C
H
H
H
H
H
H
HO
HO
Estradiol
Estrone
(´Æ¶þ´¼)
(´Æ¼¤ËØͪ )
O
OH
H3C
CH3
H
H
HO
H3C
H3C
H
H
Anfrosterone
(ÐÛçÞͪ )
H
H
H
O
Testosterone
(غÍè ¼¤ËØ)
COCH3
H3C
H3C
OH
H3C
H3C
H
H
C
H
H
H
H
O
O
Norethindrone
Progesterone
(Ȳ ŵͪ )
(»ÆÌå ͪ )
H3 C
O
H3 C
COCH2OH
OH
H
H
O
H
H3 C
HO
H3 C
H
H
H
O
Cortisone
(¿ÉµÄËÉ)
Cortisol
(Ç⻯¿ÉµÄËÉ£©
COCH2OH
OH
CH
19-6 Prostaglandins 前列腺素
Structure:
C20-carboxylic acids
a five-membered ring,
at least one double bond,
several oxygen-Containing functional groups.
O
HO
H
6
9
11
HO
5
15
H
OH
Prostaglandin E2
(Ç°ÁÐÏÙËØE2)
1
H
CO2H
CO2H
CH3
CH3
20
HO
H
OH
Prostaglandin F1a
(Ç°ÁÐÏÙËØE2)
The biosynthesis of prostaglandins of the 2 series begins with a
C20 polyenoic acid, arachidonic acid.
CO2H
2O2
cyclooxygenase
CH3
Arachidonic acid
(»¨ ÉúËÄÏ©Ëá)
H
O
several
CH3 steps
CO2H
O
H
O2H
PGC2
(»· ×´ ÄÚ¹ý Ñõ»¯Îï £©
PGE2 and other prostalandins