文档介绍：Chapter 7 Metabolism of Lipids
脂肪:甘油+ 脂肪酸(三酰甘油、甘油三脂)
类脂:磷脂、糖脂、固醇类物质
生物学功能:
良好的能源物质
生物膜和细胞质的重要成分
固醇类物质是动物激素和Vit D的前体
代谢失调会导致疾病:
如:肥胖症、血管硬化、
结石、脂肪肝、酮尿
脂类
I. Catalyzed hydrolysis of lipids
1. Hydrolyzed with lipase:
Hydrolyzate: glycerol + fatty acid
甘油三脂甘油二脂甘油单脂甘油
H2O R1COOH H2O R1COOH H2O R1COOH
2. Hydrolyzed with phospholipase:
包含:磷酸二脂酶、磷酸单脂酶。
产物:甘油二脂、磷酸、胆碱。
3. Hydrolysis of simple lipids:
简单脂类包括:胆固醇、乙酰胆碱等。
胆固醇
(胆固醇脂酶) 胆固醇+ 脂肪酸
乙酰胆碱
(胆碱脂酶) 胆碱+ 乙酰
I. Catalyzed hydrolysis of lipids
II. Catabolism of fat
1. Oxidation of Glycerol:
首先,(甘油磷酸激酶+ ATP)- 甘油
然后,( 甘油脱氢酶+ NAD+ )二羟丙酮
<Fig.> 糖酵解
Change of energy:
Activation of glycerol: -1 ATP
-甘油二羟丙酮: 1 NADH+ H+ 即3 ATP
二羟丙酮彻底氧化: PA: 2 ATP、 1 NADH+H+ 即5 ATP
乙酰CoA: 1 NADH+ H+ 即3 ATP
TCA Cycle: 共12 ATP
TOTAL: 22 ATP
2. Catabolism of fatty acid:
History:
-oxidation theory (Knoop 1904)
“activated” acetyl acid (Lehninger 1940S)
“activated” acetyl acid is acetyl CoA (Lynen 1951)
II. Catabolism of fat
Process: -oxidation of saturated fatty acid
(Fig.)
Acivation of fatty acid– fatty acyl-CoA
Dehydrogenation (-oxidation)
Hydration
Dehydrogenation (-oxidation)
Thiolysis \split
2. Catabolism of fatty acid
Concept: -oxidation
Oxidation of -C of fatty acid, which undergo 4 reactions: dehydrogenation, hydration, dehydrogenation (again) and thiolysis \split in turn, the fatty acid chain then reduce 2C and produce 1 acetyl CoA.
2. Catabolism of fatty acid
2. Catabolism of fatty acid
Position : role of carnitine <肉(毒)碱>
-oxidation of fatty acid occurred in mitochondria, while the activation of fatty acid is in cytosol.
Fatty acyl-CoA + carnitine fatty acyl-carnitine + CoA
(fatty acyl-CoA: carnitine fatty acyl transferase)
< Fatty acyl-carnitine can permeate membrane of mitochondria.>
(Fig.)
2. Catabolism of fatty acid
Energy:
Acivation of fatty acid -2 ATP
-oxidation 1 FADH +1 NADH 5 ATP
Oxidation per acetyl CoA 12 ATP
How many acetyl CoA will be produced per fatty aci