chapter 3 lipids chemistry 脂类化学
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Chapter 3 Lipids Chemistry 脂类化学. 生物化学教研室 吴映雅 Tel:13312892168. 一、 Definition 脂类概念. Lipids are non-polar (hydrophobic) compounds which can be soluble in organic solvents. 脂类是脂酰甘油 Acylglycerol 和类脂 lipoid 的总称。. 二、共同特性：. 1 、不溶于水，溶于乙醚 aether 、氯仿 chloroform 、苯 benzene 及丙酮 acetone 等有机溶剂； - PowerPoint PPT PresentationTRANSCRIPT
Chapter 3
Lipids Chemistry脂类化学
生物化学教研室
吴映雅
Tel:13312892168
一、 Definition 脂类概念
Lipids are non-polar (hydrophobic) compounds which can be soluble in organic solvents.
脂类是脂酰甘油 Acylglycerol 和类脂 lipoid的总称。
二、共同特性：
1 、不溶于水，溶于乙醚 aether 、氯仿 chloroform 、苯 benzene及丙酮 acetone 等有机溶剂；
2 、具有酯 ester 的结构，或具有成酯的可能性；
3 、可被机体所利用。
An ester forms when a hydroxyl reacts with a carboxylic acid, with loss of H2O.
Formation of an ester:
O O
R'OH + HO-C-R" R'-O-C-R'' + H2O
O P O
O
O
H2C
CH
H2C
OCR1
O O C
O
R2
X
glycerophospholipid
Each glycerophospholipidincludes a polar region:
glycerol, carbonyl 羰基 O of fatty acids, Pi, & the polar head group (X)
non-polar hydrocarbon tails of fatty acids (R1, R2).
Fatty acids 脂肪酸• Fatty acids consist of a hydrocarbon chain
with a carboxylic acid at one end.
• A 16-C fatty acid: CH3(CH2)14-COO-
• Non-polar polar
• A 16-C fatty acid with one cis double bond between C atoms 9-10 may be represented as 16:1 cis 9.
Most naturally occurring fatty acids have an even number of carbon atoms.
Double bonds in fatty acids usually have the cis configuration.
C
O
O 1
23
4
fatty acid with a cis-9 double bond
Some fatty acids and their common names:
14:0 myristic acid 肉豆蔻酸 ; 16:0 palmitic acid 棕榈酸 / 软脂酸 ; 18:0 stearic acid 硬脂酸 ; --------------saturated fatty acids 饱和脂肪酸
不饱和脂肪酸 unsaturated fatty acids
18:1 cis9 oleic acid 油酸18:2 cis9,12 linoleic acid 亚油酸18:3 cis9,12,15 -linonenic acid 亚麻酸20:4 cis5,8,11,14 arachidonic acid 花生四烯酸（ 20 个 C 、是前列腺素的前体）
20:5 cis5,8,11,14,17 eicosapentaenoic acid 二十碳五烯酸 (an omega-3)
亚油酸、亚麻酸、花生四烯酸等称必需脂肪酸
Naming of fatty acids
CH3-(CH2)7-CH=CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-COOH
C18
910
18:0, stearic acid : octadecanoic acid18:1 (9), oleic acid : octadecenoic acid
18:2 (9,12), linoleic acid : octadecadienoic acid(-6)
18:3 (9,12,15), -linolenic acid : octadecatrienoic acid(-3)
Cis 9
Essential Fatty Acids
Omega-3 (ω-3) and omega-6 (ω-6) fatty acids are unsaturated "Essential Fatty Acids" . The two EFAs are linolenic (ω-3) and linoleic (ω-6). The “3" and “6" indicate where the first double bond occurs in the fatty acid molecule.
Example: DHA (docosahexenoic acid, C22:6 ) and AA (arachidonic acid, C20:4) are both crucial to the optimal development of the brain and eyes.
Health consideration: In modern diets: ω-6 / ω-3 ratio = 15:1; Expected ratio: 2:1 to 4:1 reduced mortality from cardiovascular disease, suppressed inflammation in patients with rheumatoid arthritis (风湿性关节炎 ), and decreased risk of breast cancer.
• 类花生酸 eicosanoid• • 由花生四烯酸合成，调节细胞代谢，与炎症、
免疫、过敏、心血管疾病有关• （一）前列腺素 prostaglandin ：平滑肌松弛或
收缩等广泛生理功能• （二）血栓素 thromboxane ：凝集血小板和血
栓形成• （三）白三烯 leukotrienes ：调节白细胞、凝集
血小板等等
The Nobel Prize in Physiology and Medicine 1982
"for their discoveries concerning prostaglandins andrelated biologically active substances"
Sune K. Bergström Bengt I. Samuelsson John R. Vane
Sweden Sweden United Kingdom
b.1916 b.1934 b.1927
甘油酯类： 脂酰甘油 acylglycerol 脂肪
glyceride 磷酸甘油酯 phosphoglyceride
神经鞘磷脂 sphingomyelin
神经鞘脂类 脑苷脂 cerebroside
sphingolipid 神经节苷脂 ganglioside
( 含唾液酸 sialic acid ） 类脂
类固醇： 胆固醇 cholesterol
steroid 胆固醇酯 cholesterol ester
胆汁酸 bile acid
类固醇激素 steroid hormone 。
磷脂
糖脂
三、分类 (classification) 按化学结构分 ： 按生理功能分：
甘油酯 glyceride
• They have a glycerol backbone.
• Hydroxyls in glycerol are esterified 酯化 to
fatty acids.
C OHH
CH2OH
CH2OH
glycerol
鞘脂类 sphingolipid
• 鞘氨醇 sphingol/sphigolsine 结构
Sphingolipids are derivatives of the lipid sphingosine, which has a long hydrocarbon tail, and a polar domain that includes an amino group.
H2CHC
OH
CH
N+ CH
C
CH2
CH3
H
H3
OH
( )12
sphingosine
类固醇 steroid
• 环戊烷多氢菲结构
C holestero lH O
cholesterol PDB 1N83
第二节 甘油酯类 (glycerides)
（一）脂酰甘油 acylglycerol
甘油 + 脂肪酸酯按被酯化的 -OH 数目不同，可分为： 单酰甘油 monoacylglycerol
二酰甘油 diacylglycerol
三酰甘油 triacylglycerol
含甘油 glycerol 结构
Triacylglycerols三酰甘油
Structure: TAGs are fatty acid esters of glycerols, with each TAG made up of 1 glycerol and 3 FAs.
三酰甘油 (triacylglycerol, triglyceride) 结构：
CH O C R2
CH2 O C R1
CH2 O C R3
O
O
O
植物油：含不饱和 ( 脂肪酸多，熔点低，在室温时为液体 ----- 称“油 oil”
动物油：含饱和脂肪酸多，熔点高，在室温时为固体，称“脂”、“脂肪 fat”
脂肪性质：水解 hydrolyze 、皂化 saponify 、氢化 hydrogenate 、碘化’ iodinate 、酸败 rancidify
磷脂酸结构示意图：CH2 O C R1
CH2 O P OH
R2 C O CH
O
O
O
X
OH
X：胆碱 (choline ) 、乙醇胺 (ethanolamine ) 、丝氨酸 (serine) 、肌醇 (inositol ) 、甘油磷脂酸
第三节 磷酸甘油酯、甘油磷脂 phosph
oglycerides 、 glycerophospholipid：
Glycerophospholipids 甘油磷脂
Glycerophospholipids (phosphoglycerides 磷酸甘油酯 ), are common constituents of cellular membranes.They have a glycerol backbone.
Hydroxyls at C1 & C2 are esterified to fatty acids.
C OHH
CH2OH
CH2OH
glycerol
Phosphatidate 磷脂酸
In phosphatidate: fatty acids are esterified to hydroxyls on C1 & C2
the C3 hydroxyl is esterified to Pi.
O P O
O
O
H2C
CH
H2C
OCR1
O O C
O
R2
phosphatidate
In most glycerophospholipids (phosphoglycerides), Pi is in turn esterified to OH of a polar head group (X): e.
g., serine 丝氨酸 , choline 胆碱 , ethanolamine 乙醇胺 , glycerol, or inositol 肌醇 .
The 2 fatty acids tend to be non-identical. They may differ in length and/or the presence/absence of double bonds.
O P O
O
O
H2C
CH
H2C
OCR1
O O C
O
R2
X
glycerophospholipid
Phosphatidylinositol 磷脂酰肌醇 , with inositol as polar head group, is one glycerophospholipid.
In addition to being a membrane lipid, phosphatidylinositol has roles in cell signaling.
O P
O
O
H2C
CH
H2C
OCR1
O O C
O
R2
OH
H
OH
H
H
OHH
OH
H
O
H OH
phosphatidyl- inositol
Phosphatidylcholine, with choline as polar head group, is another glycerophospholipid.
It is a common membrane lipid.
O P O
O
O
H 2 C
C H
H 2 C
OCR 1
O O C
O
R 2
C H 2 C H 2 N C H 3
C H 3
C H 3
+
p h o sp h a tid ylc h o lin e
磷酸甘油酯作用
1 、磷脂酰胆碱 phosphatidyl choline ： 卵磷脂 lecithin , 在蛋黄中含量很高 1) 构成生物膜 cell membrane 、神经组织 nerve ti
ssue 的重要成分 2) 协助脂肪运输 fat transportation2 、磷脂酰乙醇胺 phosphatidyl ethanolamine : ( 脑磷脂 cephalin) 在脑、神经组织组织中含量高。
X ：胆碱、乙醇胺、丝氨酸、肌醇、甘油磷脂酸
神经鞘脂类 (sphingolipid )
神经鞘氨醇 ( 或二氢神经鞘氨醇 )+ 脂肪酸，1 ．神经鞘磷脂 (sphingomyelins ) ： 组成生物膜的重要成分，在脑、神经组织中含量
高。2 ．脑苷脂 (cerebrosides) ： 在神经髓鞘中含量多。 鞘糖脂3. 神经节苷脂 (gangliosides ) ： 脑灰质中含量最高，参与神经传导，与细胞免疫、
细胞识别相关。
糖脂 glycolipid 鞘糖脂 glycosphingolipid
甘油糖脂 glyceroglycolipid
作用：
细胞膜结构成分，脑、神经髓鞘成分，构成血型物质，膜抗原
糖脂
第四节 类固醇
胆固醇 (cholesterol) 结构
HO
类固醇激素 steroid hormone （甾类激素）
（一）肾上腺皮质激素 adrenocortical hormone, cortin
盐皮质激素：如醛固酮
糖皮质激素：如皮质醇（氢化可的松）
（二）性激素 sex hormone 雄性激素 male hormone 雌性激素 female hormone 雌激素 estrin 孕激素 progestogen