Lipid metabolism oxidation ppt BIOCHEMISTRY vkunder637@gmail.com

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Lipid metabolism oxidation ppt BIOCHEMISTRY vkunder637@gmail.com

  1. 1. Dr. Vijay Marakala, MBBS, MD. Assistant professor BIOCHEMISTRY SIMS & RC
  2. 2. Catabolism of FA Oxidation Anabolism of FA De-novo synthesis Ketone body metabolism Cholesterol metabolism Lipoprotein metabolism
  3. 3. Triacylglycerol Fatty acids Acetyl CoA TCA CO2 Overview of lipid metabolism
  4. 4. » Fatty acids are stored as Triacylglycerol » Constitute 84% of stored energy + Protein - 15% + Carbohydrate (glucose or glycogen) - <1% » Fatty acids mobilized from Triacylglycerol are oxidized to meet the energy needs of a cell
  5. 5. Mobilization of FA from TG into tissues Activation and transportation of FA into mitochondria Degradation of FA by oxidation into acetyl-CoA
  6. 6. Mobilization of FA from TG into tissues
  7. 7. (Adrenalin, Glucagon, ACTH) Mobilization of FA from TG into tissues
  8. 8. Mobilization of FA from TG into tissues
  9. 9. 9 Glycolysis Gluconeogenesis
  10. 10. - β-oxidation - Peroxisomal FA oxidation - α-oxidation - ω-oxidation - Modified β-oxidation pathway
  11. 11. β Oxidation of fatty acid is oxidation of fatty acid at the β carbon atom with successive removal of two carbon atoms as acetyl CoA Long assay
  12. 12. 1 • Activation of fatty acids in the cytosol 2 • Transport of activated fatty acids in to mitochondria 3 • β-Oxidation proper in the mitochondria
  13. 13. Occurs in outer mitochondrial membrane for long chain fatty acids Fatty Acid Acyl-CoA
  14. 14. CAT-I CAT-II
  15. 15. Overall process of β-oxidation 7 Cycles of β –oxidation with Successive removal of 2 carbon units Palmitoyl-CoA
  16. 16. Oxidation by FAD Hydration Oxidation by NAD Thiolysis
  17. 17. oxidation oxidation hydration thiolysis C16 7 rounds Acetyl-CoA
  18. 18. ENERGETICS OF COMPLETE OXIDATION OF PALMITIC ACID Oxidation 7 cycles 7 FADH2 x 2ATP/FADH2 14 (10.5) 7 NADH + H+ x 3ATP/NADH 21 (17.5) From 8 acetyl CoA Each acetyl CoA provides 12 ATP by TCA cycle 96 (80) Total ATP produced from one palmitic acid 131 (108) Total ATP used for activation 2 NET YIELD OF ATP 129 (106)
  19. 19. AVAILABILITY OF FATTY ACIDS Hormones Glucagon Epinephrine Insulin SYNTHESIS OF FATTY ACIDS Inhibition of carnitine acyl transferase I by malonyl CoA
  20. 20. Provision of energy • 20-30% of energy requirement of the cell • Major pathway Ketone bodies • Diabetes • Starvation Synthesis of biomolecules from acetyl CoA • Acetylcholine • Cholesterol
  21. 21. Oxidized by β–oxidation in the same way as that of even number, except the are the end products
  22. 22. β-OXIDATION OF ODD CHAIN FATTY ACIDS D L
  23. 23. • Requires additional enzymes • Isomerase and reductase Presence of double bonds
  24. 24. • Minor pathway • Involves oxdn of fatty acids at α carbon atom • One carbon is removed from the carboxyl end and released as CO2 • Occurs in endoplasmic reticulum • Phytanic acid oxidation α-OXIDATION
  25. 25.  It is a minor pathway  Takes place in microsomes  Involves oxidation of last carbon atom ( ω carbon)  More common with medium chain fatty acids
  26. 26. Disorders Carnitine deficiency Jamaican vomiting sickness Refsum’s disease Zellweger’s syndrome
  27. 27. Can occur particularly in the newborn— and especially in preterm infants Carnitine deficiency Features • Muscle cramps, muscle weakness
  28. 28. • Caused by eating the unripe fruit of the akee tree, which contains a toxin, hypoglycin, that inactivates medium and short chain acyl-CoA dehydrogenase, inhibiting β-oxidation and causing hypoglycemia. Jamaican vomiting sickness
  29. 29. Is a rare neurologic disorder due to a defect that causes the accumulation of phytanic acid, which is found in plant foodstuffs and blocks β-oxidation. Refsum’s disease Features • Cerebral ataxia • Periphaeral neuropathy • Retinitis pigmentosa
  30. 30. Occurs in individuals with a rare inherited absence of peroxisomes in all tissues. Zellweger’s syndrome

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