6-生物氧化.pptVIP

第六章 生 物 氧 化(biological oxidation) LIU Yong Research Center for Biochemistry Molecular Biology Jiangsu Key Laboratory of Brain Disease Bioinformation 生命在于运动 2. 生物氧化的本质是电子的转移 电子传递链 (electron transfer chain) 还原型底物 + NAD+ 氧化底物 + NADH + H+ 还原型底物 + NADP+ 氧化底物 + NADPH + H+ 3. 生物氧化的重要性 提供生物体生命活动所需能量 3.加氧反应 RH + 1/2O2 ROH 供电子体 受电子体 (供氢体) (受氢体) 递氢体或电子传递体(E)。 Carbohydrates Lipids Amino acids CO2  NADH/NADPH + H+, FADH2/FMNH2 Electron transfer chain H2O + ATP The inner membrane is selective permeable, or half-permeable Animation of ATP synthesis in Mitochondria Step 1: Proton gradient is built up as a result of NADH (produced from oxidation reactions) feeding electrons into electron transport system.  Step 2: Protons (indicated by + charge) enter back into the mitochondrial matrix through channels in ATP synthase enzyme complex. This entry is coupled to ATP synthesis from ADP and phosphate (Pi) The sequence of electron carriers cytochromes Determination of the sequence of electron carriers by the effects of inhibitors of electron transfer carrier. Absorption spectra of cytochrome c in its oxidized (red) and reduced (blue) forms The electron transfer chain phosphorylation on the substrate level: energy released in glycolysis and TCA cycle is recovered as ATP three reactions: in glycolysis and TCA cycle NADH---- 3ATP FADH2----2ATP Schematic diagram showing the ATP synthase complex from mitochondria (线粒体ATP合酶结构模式图） Electron transfer to O2 is tightly coupled to ATP synthesis in mitochondria 生物大分子的合成 需要 能量Assembly of Informational Macromolecules Requires Energy 体内合成核酸、糖原等生物大分子需耗费能量 在骨骼肌和大脑中，通过a-磷酸甘油穿梭运载的NADH把H传递给复合体Ⅲ，因而提供的能量只能合成2个ATP。 (糖酵解） 机体内自由基的生成 自由基对细胞的损伤 自由基的清除 掌握：呼吸链的概念；两条主要的呼吸链。 氧化磷酸化、P/O比值的概念 通