11 第十一章 脂类代谢.ppt

Section K Lipid metabolism K1. Structures and roles of fatty acids K2. Fatty acid breakdown K3. Fatty acid synthesis K4. Metabolism of triacylglycerols K5. Cholesterol metabolism K6. Lipoproteins Structures and roles of fatty acids 1.Structure and properties 2. Nomenclature 3. Roles 4.Prostaglandins Structure of fatty acid saturated fatty acid unsaturated fatty acid structure Fatty acids structure and names Fatty acid A fatty acid consists of a hydrocarbon chain and a terminal carboxylic acid group. Most fatty acids have an even number carbon atoms in an unbranched chain. Fatty acids can divided into saturated and unsaturated fatty acids according to with or without double bond. The properties of a fatty acid depend on the chain length and the number of double bonds. Nomenclature Fatty acid are named according to the number of carbon atoms in the chain and the number and position of any double bonds. Table fatty acids structure and names Roles Essential components of biological membranes. Covalently modifying proteins. Energy stores and fuel molecules. Fatty acid derivatives serve as hormones and intracellular second messengers. Lipid hormone Prostaglandins Prostaglandins 前列腺素 and the other eicosanoids 类二十烷酸 (prostacylins 前列环素, thromboxanes 凝血恶烷 and leukotrienes 白三烯) are derived from arachidonate 花生四烯酸. These compounds all act as local hormones. Arachidonic acid and some of its eicosanoid derivatives Thromboxane A2 eicosanoid PG K2. Fatty acid breakdown 1. Overview 2. Activation 3. Transport into mitochondria 4. β-Oxidation pathway 5. Oxidation of unsaturated fatty acids 6. Oxidation of odd-chain fatty acids 7. Regulation 8. Energy yield 9. Ketone bodies Overview Fatty acid breakdown brings about the oxidation of long-chain fatty acids with the production of energy in the form of ATP. Fatty acid breakdown include β-oxidation (fatty acid de