1

Chapter 3. Lipids

I. IntroductionII. Storage lipidsIII. Structural lipidsIV. Active lipidsV. Glycolipids and lipoproteinsVI. Separation and analysis of lipids

Biological lipids are a chemically diverse group of compounds, which are highly soluble in nonpolar solvents but not in water. They are either hydrophobic or amphipathic.

2

I. IntroductionConsiderations Classifications Explanations

Chemical compositions

Simple lipids

( 单纯脂质 )

Esters of fatty acids and glycerol

e.g. triacylglycerol, wax

( 化学成分 ) Compound lipids

( 复合脂质 )

e.g. phospholipids, glycolipids

Derived lipids

( 衍生脂质 )

Derived from/related to the above

e.g. fatty acids, steroids, terpenes,

Saponification Saponifiable lipids Can be hydrolyzed by KOH

( 皂化 ) Unsaponifiable lipids e.g. terpenes, steroids

Polarity ( 极性 ) Polar lipids Na carboxylate with a long chain

Nonpolar lipids Ester of long-chain fatty acid and alcohol

Biological Storage lipids Energy storage

Functions Structural lipids Membrane constituents

( 生物功能 ) Active lipids As enzyme cofactors, electron carriers, etc.

P.79

3

Membrane structure

4

Amphipathic lipid aggregates that form in water

Vesicle

两亲性

EmulsionEmulsification

Sodium dodecyl sulfate (SDS)

Critical micelle concentration (CMC)

5

Biological Functions

Lipids

Storage lipids( 贮存脂质 )

Structural lipids( 结构脂质 )

Active lipids( 活性脂质 )

Fatty acids ( 脂肪酸 )Triacylglycerols ( 三酰甘油 )Wax ( 蜡 )

Phospholipids ( 磷脂 )Glycolipids ( 糖脂 )Sterols ( 甾醇 )

Terpenes ( 萜 )Steroids ( 类固醇 )Lipoproteins ( 脂蛋白 )

I. Introduction

P.80

6

II. Storage Lipids

1.1. Fatty acids (Fatty acids ( 脂肪酸脂肪酸 ))

2.2. Triacylglycerols (Triacylglycerols ( 三酰甘油三酰甘油 ))

3.3. Wax (Wax ( 蜡蜡 ))

1. Fatty acids

(1) Compositions & classifications ( 组成和分类 )

(2) Saturated and unsaturated fatty acids ( 饱和与不饱和脂肪酸 )

(3) Nomencluture ( 命名 )

(4) Fatty acids in food

(5) Essential fatty acids ( 必需脂肪酸 )

(6) Physical properties

(7) Chemical properties

7

II. Storage

lipids

8

(1). Compositions & classifications( 组成和分类 )

Fatty acid

‘Tail’ – hydrophobic chain (C4-C36)

‘Head’ – hydrophilic group (-COO-)

Saturated( 饱和脂肪酸 )

Unsaturated( 不饱和脂肪酸 )

Monounsaturated( 单不饱和脂肪酸 )

Polyunsaturated( 多不饱和脂肪酸 )

Most common:Even No. of C ( 偶数 C)Unbranched ( 无支链 )C12-C24

疏水长链

亲水基团

9

(2). Saturated and unsaturated fatty acidsSaturated fatty acids ( 饱和脂肪酸 ):

Flexible structure, with the fully extended conformation the most stable ( 结构灵活 )

Close packing ( 紧密堆积 ) High melting point ( 高熔点 , e.g. beef oil)

Unsaturated fatty acids ( 不饱和脂肪酸 ) : Slightly more abundant in nature ‘Kinks’ in the chain – resulting in flexible, fluid aggregates The most common one is oleic acie ( 油酸 ): 18:1 9c

C=C bond usually in cis-form, rarely in trans-form Common location of C=C bonds:

Monounsaturated: C9=C10

Polyunsaturated: C9=C10, C12=C13, C15=C16,

II. Storage

lipids

10

(3). Nomencluture ( 命名 )

18:29c,12cChain length( 链长 , 总 C 数 )

No. of C=C bonds( 双键数 )

Position of C=C bonds( 双键的位置 )

cis-trans configuration of C=C( 双键的顺反构型 )

Common name

( 俗名 )

Systematic name

( 系统名 )

Symbol

( 符号 )

Structure

( 结构 )

Stearic acid

硬脂酸n-Octadecanoic acid

(n- 十八酸 )

18:0 CH3(CH2)16COOH Saturated

( 饱和 )

Linoleic acid

亚油酸cis, cis-9,12-octadecadienoic acid ( 十八碳 -9,12- 二烯酸 )

18:29c,12c CH3(CH2)4(CH=CHCH2)2

(CH2)6COOHUnsaturated

( 不饱和 )

11

12

Vegetable oils vs. animal oils and fats Unsaturated fatty acids vs. saturated fatty acids Unsaturated fatty acids: cis vs. trans Trans fat and hydrogenated vegetable oil

Example 1. Olive oil – rich in oleic acid (monounsaturated)

Example 2. Margarine – a substitute for butter

(4). Fatty acids in food

II. Storage

lipids

Source 月桂酸，豆蔻酸 棕榈酸 硬脂酸 油酸 亚油酸

12:0, 14:012:0, 14:0 16:016:0 18:018:0 18:118:19c9c 18:218:29c,12c9c,12c

Beef 55 24-3224-32 20-2520-25 37-4337-43 2-32-3

Coconut 7474 1010 22 77

Olive 99 22 8484 44

Sunflower 66 11 2121 6666

13

Partial hydrogenation of cooking oilsshelf lives ( m.p.∵ ) trans fatty acids

Higer incidence of cardiovascular

disease

— — those that are not synthesized those that are not synthesized by mammals and yet are by mammals and yet are necessary for normal growth necessary for normal growth and life.and life.

(5). Essential fatty acids (EFA, 必需脂肪酸 )

棕榈酸

硬脂酸

油酸

亚油酸

ALA, 亚麻酸

花生四烯酸

棕榈油酸

Eicosapentaenoic acid (EPA)20:5(5,8,11,14,17)十二碳五烯酸

Docosahexaenoic acid (DHA)22:6(4,7,10,13,16,19)二十二碳六烯酸

Omega-3 (-3) fatty acidsPolyunsaturated fatty acids (PUFAs) with a double bond between C3 and C4 from the methyl end of the chain.

Specially important in human nutrition

Optimal dietary ratio:

15

-6 PUFAs

-3 PUFAs= 1:1 ~ 4:1

亚麻酸， 18:3(9,12,15):

-linolenic acid (ALA), an -3 fatty acid

-linolenic acid (GLA), an -6 fatty acid

16

-linolenic acid (ALA)18:3(9,12,15) 亚麻酸

Eicosapentaenoic acid (EPA)20:5(5,8,11,14,17)十二碳五烯酸

Essential fatty acidHumans can synthesize EPA and DHA from ALA

Docosahexaenoic acid (DHA)22:6(4,7,10,13,16,19)二十二碳六烯酸

All the 3 are -3 fatty acids, all important in cellular function.

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(6) Physical properties ( 物理性质 )

Chain length ( 烃链长度 )

Unsaturation degree ( 烃链的不饱和程度 )

Hydrocarbon tail( 烃链 )

Carboxylic head( 羧基头 )

Modified, e.g. esterified( 如：脂肪酸酯化 )

Solubility ( 溶解度 )

Melting point ( 熔点 )

Fatty acid Solubility

6:0 9.7 mg/g

12:0 0.055 mg/g

18:0 0.003 mg/g

Fatty acid m.p. Fatty acid m.p.

18:0 69.6oC 14:0 53.9oC

18:19c 13.4oC 14:19c 4.5oC

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Oxidation (Oxidation ( 氧化氧化 ) ) and peroxidation (and peroxidation ( 过氧化过氧化 )) Addition (Addition ( 加成加成 ))

Hydrogenation (Hydrogenation ( 氢化氢化 )) Halogenation (Halogenation ( 卤化卤化 ))

Emulfication (Emulfication ( 乳化乳化 )): Amphipathy (: Amphipathy ( 两亲性两亲性 ))

Emulsifier (Emulsifier ( 乳化剂乳化剂 ))

Detergent (Detergent ( 去污剂去污剂 ))

Surfactant (Surfactant ( 表面活性剂表面活性剂 ))

(7). Chemical properties

S

O

O

O-O Na+

十二烷基硫酸钠(Sodium dodecyl sulfate, SDS)

Ionic detergent

II. Storage

lipids

P.86

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2. Triacylglycerols ( 三酰甘油 )

1). Triacylglycerol ( 三酰甘油 ) = Triglyceride ( 甘油三脂 ), TG-- Triester of glycerol with 3 fatty acids ( 甘油和脂肪酸形成的三酯 )

2). The central C is a prochiral center-- sn-system

3). Classification:Simple triacylglycerol ( 简单三酰甘油 )

Triolein ( 三油酸甘油脂 )Tristearin ( 三硬脂酸甘油脂 )

Mixed triacylglycerol ( 混合三酰甘油 )1- 棕榈酰 -2- 硬脂酰 -3- 豆蔻酰 -sn- 甘油

H2C

HC OH

H2C OH

OH H2C

HC O

H2C O

O C

C

C

O

O

O

R1

R2

R3

Glycerol Triacylglycerol

简单三酰甘油酰甘油 : : R1 = R2 = R3R1 = R2 = R3混合三酰甘油混合三酰甘油 : : R1, R2, R3R1, R2, R3 不完全相不完全相同同

Monoacylglycerol ( 单酰甘油 )Diacylglycerol ( 二酰甘油 )Triacylglycerol ( 三酰甘油 )

P.91

Nomencluture of glycerol derivatives: sn-system(Stereospecific numbering system)

C

CH2-OPO3-

HO

CH2OH

H C

CH2OH

H

CH2-OPO3-

OH

L-Glycerol-3-phosphate D-Glycerol-1-phosphate

C2

Cb

Ca OH

C2

CbH2OH

HO

CaH2OH

H

C2

Cb

CaOH

C2

Cb

Ca OH

S-configuration at C2

R-configuration at C2

Ca -- Pro-S

Ca is denoted as C1

Cb -- Pro-R

Cb is denoted as C3

Slightly increase the priority of Ca

Slightly increase the priority of Cb

sn-Glycerol-3-phosphate

C

CH2OH

HO

CH2-OPO3-

H

sn-Glycerol-1-phosphate

sn- 甘油 -3- 磷酸

L-configuration

21

General structrure of a triacylglycerol

Hydrolysis by:H+

OH-

Lipases ( 脂肪酶 )

Oil ( 油 ) – liquidFat ( 脂 ) – solid

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4) Physical properties ( 物理性质 ):a. Color and odor ( 颜色和气味 )

Colorless, odorless, tasteless

b. Density and solubility ( 密度和溶解度 )Density < 1 g/cm3

Insoluble in H2O, soluble in nonpolar solventsTGs are nonpolar, hydrophobic molecules:

c. Melting point ( 熔点 )Chain length, m.p.Double bonds, m.p.Olive oil – liquidBeef fat – solid

2. Triacylglycerols (continued)

II. Storage

lipids

P.93

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5) Chemical properties ( 化学性质 ):a. Hydrolysis ( 水解 ) and saponification ( 皂化 )

-- Saponification value ( 皂化值 )-- Used for estimation of the molecular weight ( 用于估计分子量 ).

b. Hydrogenation ( 氢化 ) and halogenation ( 卤化 )-- Iodine value ( 碘值 )-- Used for estimation of the unsaturation degree ( 用于估计不饱和度 ).

c. Acetylation ( 乙酰化 )-- Acetylation number ( 乙酰值 )-- Used for estimation of the number of free –OH ( 用于估计自由羟基数 )

d. Rancidity ( 酸败 ) and autoxidation ( 自动氧化 )-- Acid value ( 酸值 )-- Used for estimation of the rancidity degree ( 用于估计酸败程度 )

2. Triacylglycerols (continued)

II. Storage

lipids

P.94

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Saponification value is the mg of KOH required to saponify 1g of a TG ( 皂化值是皂化 1g 三酰甘油所需要的 KOH 的 mg 数 ).

It can be used to estimate the molecular weight of a TG ( 皂化值可帮助估计三酰甘油的分子量 ).

x

y

Saponification value ( 皂化值 )

H2C

HC OH

H2C OH

OHH2C

HC O

H2C O

O C

C

C

O

O

O

R1

R2

R3

GlycerolTriacylglycerol

+ 3 KOH

R1COO-

R2COO-

R3COO-

+

1

y

x/1000

KOH: = 1: 3

分子量

皂化值

25

Iodine value ( 碘值 ) The iodine value represents how many grams of I2 are

required for the halogenation reaction of 100 g of a TG ( 碘值指 100g 油脂卤化时所能吸收碘的克数 )

It can be used to estimate the unsaturation level of the TG ( 碘值可用于估计油脂的不饱和度 )

Suppose the TG contains y double bonds,

C C + I2 CI CI

100

MW

x

y

x

I2

= 1 : y:

TG 分子量

碘值

TG 不饱和键数

26

Acetylation number ( 乙酰值 )

It is the mg of KOH required to neutralize the CH3COOH released from 1 g of an acetylated product ( 乙酰值指从1g 油脂乙酰化产物中释放的乙酸所需的 KOH 的 mg数 ).

It is used to represent how many hydroxyl groups are available in the TG ( 用于表示油脂的羟基化程度 ).

R-OH CH3COOR CH3COOH : KOHAcetylation Hydrolysis

乙酰化 水解

x

y

1

MW

x/1000

KOH: = 1: y

TG 分子量

乙酰值

TG 的自由羟基数

27

Acid value ( 酸值 )

It is the mg of KOH required to neutralize the free It is the mg of KOH required to neutralize the free fatty acids released from 1 g of a TG (fatty acids released from 1 g of a TG ( 酸值是中和酸值是中和 1 g1 g油脂中的游离脂肪酸所需的油脂中的游离脂肪酸所需的 KOHKOH 的的 mgmg 数数 ))

It is used to estimate the rancidity degree of the TG ( 用于估计油脂的油脂的酸败程度 )

Two major reasons for rancidification ( 酸败 ): Autoxidation ( 自氧化 ) Microbial effects ( 微生物效应 )

28

6) 6) Major use of TGs in animals and plantsMajor use of TGs in animals and plants Energy storageEnergy storage InsulationInsulation Examples: Polar bears & Sperm whalesExamples: Polar bears & Sperm whales

2. Triacylglycerols (continued)

The mighty whales swim in a sea of water, and have a sea of oil swimming in them.

II. Storage

lipids

Triglycerols vs. starch/glycogen

More reduced more energy to be released when oxidized

More hydrophobic no need to carry extra water for hydration

29

2 advantages of using triglycerols as stored fuels

The human body can storeFats – to meet energy needs for months

Glycogen – less than a day’s energy supply

Glucose and glycogen can work as quick sources of metabolic energy ( ready solubility in water)∵

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1)1) Esters of long-chain fatty acids with long-chain Esters of long-chain fatty acids with long-chain alcoholsalcohols

2)2) Energy stores and water repellentsEnergy stores and water repellents

3)3) ApplicationsApplications

3. Wax

Triacontanoylpalmitate, the major component of beeswax

II. Storage

lipids

P.95

C14-C36 C16-C36

Weakly polar head group

Nonpolar tails

31

A honeycomb constructed of beeswax

32

III. Structural Lipids

1. Glycerophospholipids ( 甘油磷脂 )

2. Glycolipids ( 糖脂 )

3. Archaeal ether lipids ( 古细菌醚脂 )

4. Sphingolipids ( 鞘脂类 )

5. Sterols ( 甾醇 )

Principal classes of storage and membrane lipids

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磷脂 糖脂

膜脂

phosphosphingolipids鞘磷脂

（鞘氨醇磷脂）

glycosphingolipids鞘糖脂

古细菌醚脂

Sphingolipids( 鞘脂类 )

鞘氨醇

Sterols ( 甾醇 )

甘油磷脂三酰甘油

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Glycerophospholipids ( 甘油磷脂 )‖

Phosphoglycerides ( 磷酸甘油脂 )

1. Glycerophospholipids ( 甘油磷脂 )

CH2

CH

H2C O

OC

O

OCC

O

P O X

O

O-

Nonpolar tail ( 非极性尾部 )

Polar head( 极性头 )

C-1: C16 or C18, saturated fatty acid

C-2: C18 or C20, unsaturated fatty acid

III. Structural

Lipids

P.103

D-Glycerol 3-phosphate, the backbone of phospholipids

35

磷脂酸

磷脂酰胆碱( 卵磷脂 )

lecithin

磷脂酰乙氨醇( 脑磷脂 )cephalin

两亲性手性电荷

The charge on the polar head contributes greatly to the surface properties of membranes

36

2. Glycolipids ( 糖脂 )

Galactolipids ( 半乳糖脂 ) and sulfolipids ( 硫脂 ) are predominate in plant cells.

Galactolipids are localized in the thylakoid ( 类囊体 ) membranes of chloroplasts, making up 70-80% of the total membrane lipids of a vascular plant.

Galactolipids are probably the most abundant membrane lipids in the biosphere. 3 glycolipids of chloroplast thylakoid

membranes

37

3. Archaeal ether lipids ( 古细菌醚脂 ) Archaea contain unique membrane lipids – ether lipids. The general name for these lipids: glycerol dialkyl glycerol

tetraethers (GDGTs) These ether linkages are much more stable to hydrolysis at low

pH and high temperature. Archaea live in ecological niches with extreme conditions: e.g.,

high temperature, low pH, high ionic strength.

A typical membrane lipid of archaea

Long chain (32 carbons) branched hydrocarbons

38

4. Sphingolipids ( 鞘脂类 )

CH

HCHN

H2C O

CH=CH

X

(CH2)12-CH3HO

C

O

神经酰胺 (ceramide) ： X = H鞘磷脂 (phosphosphingolipid): X = 磷酰胆碱，磷酰乙醇胺鞘糖脂 (glycosphingolipid): X = 单糖，寡糖

Sphingosine ( 鞘氨醇 ) as the backbone

Fatty acid chainIII. Structural

Lipids

两亲性手性电荷

Sphingolipids at cell surfaces are sites of biological recognition

39

CH2 – O – P – O – CH2 – CH2 – N+(CH3)3

O

O-

HO – CH – CH = CH – (CH2)12 – CH3

CH – NH – C – (CH2)14 – CH3

Sphingosine( 鞘氨醇 ) Fatty acid

( 脂肪酸 )

Phosphocholine( 磷酰胆碱 )

O

Phosphosphingolipids 鞘氨醇磷脂(Sphingomyelin 鞘磷脂 )

P.107

Sphinogomyelins are present in the plasma membranes of animal cells and are especially prominent in myelin, a membranous sheath that surrounds and insulates the axons of some neurons – thus the name “sphingomyelins”.

40

Sphinogolipid

s

神经节苷脂

神经酰胺

( 神经 ) 鞘磷脂

红细胞糖苷酯

脑苷脂

Phosphosphinogolipid( 鞘磷脂 )

Glycosphingolipids( 鞘糖脂 )

41

Glycosphingolipids as determinants of blood groups

Type O blood – universal donorType AB blood – universal receiver

血型 红细胞 血清凝集原 凝集素

抗原 抗体A A 抗 B

B B 抗 A

AB A, B

O 抗 A, 抗B

III. Structural

Lipids

P.63

42

CH2 – O – C – R1

O

CH2 – O – P – O – X

O

O-

R2 – C – O – CH

O

Phospholipase A2

Phospholipase A1

Phospholipase C Phospholipase D

H+, OH-

H+, Strong OH-

H+, OH-

H+

Phospholipase磷脂酶

Phospholipids and sphingolipids are degraded in lysosomes ( 细胞溶酶体 )

III. Structural

Lipids

P.105

43

Sphingomyelins and gangliosides are degraded by a set of lysosomal enzymes.

A genetic defect in any of these enzymes may lead to severe medical consequences.

44

Disease Niemann-Pick Tay-Sachs

Deficient enzyme Sphingomyelinase -Hexosaminidase A

Accumulated substance Sphingomyelin Ganglioside

Prognosis Early death Early death

Fatal diseases related togenetic lipid storage disorder

鞘磷脂 鞘糖脂

45

5. Sterols ( 甾醇 ) structural lipids present in the membranes of most eukaryotic cells

Major constituents of plasma membrane and plasma lipoproteins ( 细胞质膜和脂蛋白的主要组成 )

Precursors of other steroids ( 生成其它类固醇的前体 )

Cholesterol ( 胆固醇 ) Sterol’s roles

P.112

Cholesterol is the major sterol in animal tissues.

( 牛磺胆酸 )

( 胆汁酸 )

Bacteria cannot synthesize sterols.

46

Steroids derived from cholesterol( 从胆固醇衍生出来的类固醇 )

睾丸激素 雌二醇

皮质 ( 甾 ) 醇 醛甾酮

脱氢皮质 ( 甾 ) 醇 强的松

Androgens ( 雄性激素 ) – testosterone ( 睾丸激素 )

Estrogens ( 雌激素 ) – estradiol ( 雌二醇 )

Progestins ( 孕激素 ) – progesterone ( 孕酮 )

Glucocorticoids ( 糖 ( 肾上腺 ) 皮质激素 ) – cortisol

Mineralocorticoids ( 盐皮质激素 )肾上腺皮质激素 黄铜质

5 families of hormones

47

IV. Active Lipids Signals – e.g. Steroid hormones, vitamins A & D Cofactors/electron carriers – e.g. coenzyme A, vitamins E & K Pigments – e.g. -carotene ( 胡萝卜素 ) A large group of volatile lipids produced in plants serve as signals

passing through the air

角黄素

玉米黄质

48

Terpenes and steroids( 萜和类固醇 )

Active lipids ( 活性脂质 ) Unsaponifiable lipids ( 非皂化脂 ) Different from other lipids: containing no fatty acids ( 不含

脂肪酸 ) Terpenes: composed of isoprene units ( 异戊二烯单位 ) Steroids: composed of steroid nucleus ( 甾核 )

Sterols ( 甾醇 )

Zoosterol( 动物固醇 )

Phytosterol( 植物固醇 )

Cholesterol( 胆固醇 )

-sitosterol( 谷固醇 )

P.110

49

C

CH3

C

CH2

H2C

H

Isoprene (C5)

Head-to-tail linkage

Tail-to-tail linkage

Lycopene (C40, 番茄红素 )

Monoterpene (C10) – 单萜Sesquiterpene (C15) – 倍半萜Diterpene (C20) – 双萜Tetraterpene (C40) – 四萜

Terpenes ( 萜 )P.110-112

50

Some biologically active isoprenoid compounds or derivatives

泛醌 , 辅酶 Q

质体醌

长醇

杀鼠灵

IV. A

ctive L

ipids

51

V. Glycolipids and Lipoproteins( 糖脂和脂蛋白 )

Glycolipids ( 糖脂 ):Compounds formed by covalent linkage of lipids and saccharides via glycosidic bonds( 糖和脂通过糖苷键相连 )

Lipoproteins ( 脂蛋白 ):Complexes formed by noncovalent interaction between lipids and proteins( 脂和蛋白质之间非共价结合 )

III. Structural

Lipids

52

Glycolipids ( 糖脂 )

Glyceroglycolipids (Glyceroglycolipids ( 甘油糖脂甘油糖脂 )) Glycosphingolipids (Glycosphingolipids ( 鞘糖脂鞘糖脂 ))

III. Structural

Lipids

Glycolipids are also membrane lipids-- serving as structural constituents in the cell-- providing sites for biological recognition

53

Lipoproteins ( 脂蛋白 ) Lipoproteins are aggregrates of lipids and proteins (Lipoproteins are aggregrates of lipids and proteins ( 脂蛋脂蛋

白是脂和蛋白质的非共价结合物白是脂和蛋白质的非共价结合物 )) Noncovalent interactions (Noncovalent interactions ( 非共价结合非共价结合 )) Present in plasma -- also called plasma lipoproteins (Present in plasma -- also called plasma lipoproteins ( 血血浆脂蛋白浆脂蛋白 ))

Role: to carry water-insoluble lipids in blood (Role: to carry water-insoluble lipids in blood ( 在血液在血液中运载非水溶性的脂中运载非水溶性的脂 ))

Apolipoproteins (Apolipoproteins ( 载脂蛋白载脂蛋白 )) To increase solubility of the hydrophobic lipids (To increase solubility of the hydrophobic lipids ( 增加增加

脂的溶解度脂的溶解度 )) To act as specific sites for recognition by the To act as specific sites for recognition by the

lipoprotein acceptorslipoprotein acceptors ( ( 为脂蛋白受体提供识别位点为脂蛋白受体提供识别位点 ))

III. Structural

Lipids

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Classifications of lipoproteinsClassification Density

Chylomicron

( 乳糜微粒 )

0.92~0.96

Very low density lipoprotein

VLDL 0.95~1.006

Intermediate density lipoprotein

IDL 1.006~1.019

Low density lipoprotein

LDL 1.019~1.063

High density lipoprotein

HDL 1.063~1.21

Densities:Proteins – 1.3-1.4 g/cm3

Lipids – 0.8-0.9 g/cm3

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Diameter:100-500 nm

80% of mass

As signals

Molecular structure of a chylomicron

( 乳糜微粒的结构 )

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1. Lipid extraction (萃取 )

2. Adsorption chromatography ( 吸附层析 )

3. Thin layer chromatography (薄层层析 )

4. Gas-liquid chromatography ( 气相色谱 )

5. High-performance liquid chromatography ( 高压液相色谱 )

6. Specific hydrolysis (专一性水解 )

7. Mass spectrometry ( 质谱 )

VI. Separation and Analysis of Lipids