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Succinyl-CoA

Succinyl-CoA. Fatty Acid Metabolism. Phospholipase A 1. Phospholipase A 1. Phospholipase A 2. FADH 2. Glycerol = GAP + NADH - ATP. If: GAP = 2 ATP + NADH + Acetyl-CoA. Then: glycerol = Acetyl-CoA + 2 NADH + ATP. If: Acetyl-CoA = 3 NADH + FADH 2 + GTP.

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Succinyl-CoA

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  1. Succinyl-CoA

  2. Fatty Acid Metabolism

  3. Phospholipase A1 Phospholipase A1 Phospholipase A2

  4. FADH2

  5. Glycerol = GAP + NADH - ATP If: GAP = 2 ATP + NADH + Acetyl-CoA Then: glycerol = Acetyl-CoA + 2 NADH + ATP If: Acetyl-CoA = 3 NADH + FADH2 + GTP Then: glycerol = 5 NADH + GTP + ATP + FADH2 If: NADH = 3 ATP, FADH2 = 2 ATP and GTP = ATP Then: glycerol = 19 ATP

  6. 1 NADH is converted to FADH2: 1 less ATP

  7. Fatty acid + CoA + ATP ---> Fatty acyl-CoA + AMP + PPi AMP + ATP ---> 2 ADP ADP + Pi ---> ATP You essentially consume 2 ATP to activate FFAs

  8. Claisen cleavage reaction: reverse of citrate synthase

  9. Thiolase

  10. For a saturated fatty acid with n carbon atoms (even number) -oxidation yields n-2/2 NADH n-2/2 FADH2 You make n/2 Acetyl-CoA, which enter TCA cycle to yield 3n/2 NADH n/2 FADH2 n/2 ATP 3ATP per NADH 2ATP per FADH2 Lost in activation Cn:0 yields (n-2/2 + 3n/2)3ATP + (n-2/2 + n/2)2ATP + n/2 ATP - 2ATP

  11. What about unsaturated fatty acids?

  12. For every double bond an odd number of carbons away from carbonyl: 3 round -oxidation Attempt 4th round Doesn’t work

  13. Ready for another round of oxidation: however no FADH2 produced. This ultimately costs 2 ATP in the end.

  14. For every double bond an even number of carbons away from carbonyl: 5 rounds -oxidation Neither dehydrogenase nor isomerase recognize ∆4 unsaturated fatty acids as a substrate.

  15. Just reduce the double bond Resume oxidation with the cost of 1 NADPH which ultimately costs one NADH and 3 ATP in the end.

  16. What about fatty acids with odd number carbons Last round produces propionyl-CoA instead of Acetyl-CoA

  17. For odd chain fatty acids You make n-3 Acetyl-CoA and one propionyl-CoA One extra ATP is consumed to convert propionyl-CoA to succinyl-CoA Succinyl-CoA enters TCA cycle This is can be used as an anapleurotic rxn or the succinyl-CoA can be converted to malate. In the latter case.....

  18. Conversion of succinyl-CoA to malate makes 1 ATP, 1 FADH2

  19. Malate Malic enzyme - decarboxylating +1 NADPH pyruvate 4 NADH + 1 FADH2 + ATP

  20. So.....for odd chain fatty acids You make n-3 Acetyl-CoA and one propionyl-CoA One extra ATP is consumed to convert propionyl-CoA to succinyl-CoA One ATP and one FADH2 are made to convert succinyl-CoA into malate One NADPH is made converting malate into pyruvate Pyruvate = 4 NADH, 1 ATP and 1 FADH2 So….propionyl-CoA = 2 FADH2 + 4 NADH + 1ATP + NADPH Cn(odd):0 yields (n-3/2 + 3n-3/2 + 4)3ATP + (n-3/2 + n-3/2 + 2)2ATP + (n-3/2 + 1) ATP - 2ATP + NADPH

  21. The glyoxosome is a special peroxisome in germinating seeds that uses Acetyl-CoA from triacylglycerol to make glucose

  22. -oxidation: in the ER

  23. -oxidation: peroxisome

  24. Ketone Bodies Muscle Liver

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