3.脂酸的B氧化 (线粒体) RCH2CH2C~SCoA 脂酰CoA FAD 脱氢 脂酰CoA 脱氢酶 FADH2 RCH=CHC-SCoA 反2-烯酰CoA 加水 2-烯脂酰CoA H20 水化酶 3 R忌HOHCH,.C-SCoA L(+)-β羟脂酰CoA 再脱氢 L(+)β羟脂酰 NAD* CoA脱氢酶 NADH+H* B a Q RCOCH,C-SCoA B酮脂酰CoA 硫解 B酮脂酰CoA 硫解酶 CoA-SH RC-SCoA CH CO-SCoA 脂酰CoA+乙酰CoA
3. 脂酸的β氧化 脱氢 加水 再脱氢 硫解 脂酰CoA L(+)-β羟脂酰CoA β酮脂酰CoA 脂酰CoA+乙酰CoA 脂酰CoA 脱氢酶 反⊿2 -烯酰CoA L(+)-β羟脂酰 CoA脱氢酶 NAD+ NADH+H+ ⊿2 --烯脂酰CoA 水化酶 H2O FAD FADH2 β酮脂酰CoA 硫解酶 CoA-SH RCH=CHC~SCoA β α O = RCH=CHC~SCoA β α O = RCH2CH2C~SCoA = O RCHOHCH2C~SCoA β α = O RCOCH2C~SCoA β α = O RC~SCoA + CH3CO~SCoA = O (线粒体)
(C1)R-CH2-CH2-CH2- Q S-CoA Palmitoyl-CoA acyl-CoA FAD C14 →Acetyl-CoA dehydrogenase FADH H C12 →Acetyl-CoA R-CH2-C-C-C- S-CoA trans-12. Enoyl-CoA →Acetyl-CoA enoyl-CoA H20 00 hydratase OH →Acetyl-CoA R-CH2 C-CH2- S-CoA H L-B-Hydroxy- acyl-CoA NAD →Acetyl-CoA B-hydroxyacyl-CoA dehydrogenase NADH H* R-CH2-C-CH2-C- S-CoA →Acetyl-CoA 0 B-Ketoacyl-CoA acyl-CoA CoA-SH acetyitransferase (thiolase】 Acetyl-CoA (C14)R-CH2- C S-CoA+CH:- C-S-CoA 0 (C1)Acyl-CoA Acetyl-CoA (myristoyl-CoA) (b) (a)
RCH,CH,C~SCoA RCH,CH,C~SCoA AMP 脂酰CoA FAD 2ATP PPi 肉碱 脱氢酶 FADH2 H20 脂酰CoA RCH-CHE-SCOA 呼吸链 合成酶 ATP CoASH 转运载体 -烯酰COA H20 9 水化酶 RCH,CH,C-OH 3 RCHOHCH,C-SCOA 脂肪酸 L(+)β羟脂酰 NAD* 3ATP CoA脱氢酶 NADH+H+ H2O 呼吸链 RCoH.&-SCOA 线粒体膜 B酮脂酰CoA 硫解酶 CoA-SH TAC 8 RC~SCoA CH,CO-SCoA
脂酰CoA 脱氢酶 L(+) - β羟脂酰 CoA脱氢酶 NAD+ NADH+H+ ⊿--烯酰CoA 水化酶 2 H 2 O FAD FADH 2 β酮脂酰CoA 硫解酶 CoA -SH 脂酰CoA 合成酶 肉碱转运载体 ATP CoASH AMP PPi H 2 O 呼吸链 2ATP H 2O 呼吸链 3ATP 线粒体膜 TAC 脂 肪 酸 RCH 2CH 2 C -OH =O RCH =CHC~SCoA β α O = RCH =CHC~SCoA β α O = RCH 2CH 2C~SCoA = O RCHOHCH 2C~SCoA β α = O RCOCH 2C~SCoA β α = O RC~SCoA + CH 3CO ~SCoA =ORCH2CH2C~SCoA = O
4.脂酸氧化的能量生成 以16碳软脂酸的氧化为例 活化：消耗2个高能磷酸键 B氧化： 每轮循环 四个重复步骤：脱氢、水化、再脱氢、硫解 产物：1分子乙酰CoA 1分子少两个碳原子的脂酰C0A 1分子NADH+HH 1分子FADH2
活 化：消耗2个高能磷酸键 β氧 化： 每轮循环 四个重复步骤：脱氢、水化、再脱氢、硫解 产物：1分子乙酰CoA 1分子少两个碳原子的脂酰CoA 1分子NADH+H+ 1分子FADH2 4. 脂酸氧化的能量生成 —— 以16碳软脂酸的氧化为例
Stage 1 Stage 2 CH3 7轮循环产物：8分子乙酰CoA CH2 CH2 BOxidation CH2 8 Acetyl-CoA 7分子NADH+HH CH2 CH2 7分子FADH2 CH2 CH2 CH2 >CH2 Citric CH2 acid cyele CH2 CH2 CH2 64e CH2 16C02 能量计算： C=0 生成ATP 8×12+7×3 Stage 3 NADH,FADH2 +7X2=131 2H+02 Respiratory 净生成ATP (electron transfer) chain H20 131-2=129 ADP Pi ATP
7 轮循环产物：8分子乙酰CoA 7分子NADH+H+ 7分子FADH2 能量计算： 生成ATP 8×12 + 7×3 + 7×2 = 131 净生成ATP 131 – 2 = 129