fat metabolism

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Fat Metabolism


  • Fat MetabolismIm not fat, Ive just got a lot of potential energy!

  • Digestion, Mobilization, and Transporthttp://courses.cm.utexas.edu/emarcotte/ch339k/fall2005/Lecture-Ch17-1/Slide2.JPG

  • EmulsificationFats are not water solubleMade into bile salts that areAbsorbed as micelles in small intestines

  • Chylomicron Carriersproteins that carry fatsstored in adipose tissue

  • Role of HormonesCan mobilize from adiposeRelease as Fatty acidsEpinephrene and glucagon release cAMPmake fatty acids and glycerolmobilizes fat

  • Animation of Processhttp://www.wiley.com/legacy/college/boyer/0470003790/animations/fatty_acid_metabolism/fatty_acid_metabolism.htmFUN!

  • Activation and Transported to MitochondriaFA + CA --> ATP = FA-CoA + AMP + PpiDriven by breakup of PpiAcyl CoA Synthetase-32.5 kJTransported through inner mito membrane via carnitineuses specific acyl carnitine transporter

  • Carnitine

  • Formation of acyl carnitineCan get transported across inner mitochondrial membrane

  • Animation of Processhttp://www.brookscole.com/chemistry_d/templates/student_resources/shared_resources/animations/carnitine/carnitine1.html

  • Beta Oxidation Breakdown of fats into Acetyl coenzyme A --> Kreb CycleFADH2 --> Oxidative PhosphorylationNADH--> Oxidative PhosphorylationBreaks off two carbons at a time to acetyl CoARemaining goes another round

  • Reactions Diagram

  • Reactions of Beta Oxidation Acyl-CoA Dehydrogenase

    Puts in a double bondOxidizes C-C bond to double bondProduces FADH2

  • Reactions of Beta oxidationEnoyl CoA Hydratase

    adds waterforms -hydroxy product

  • Reactions of Beta Oxidation -hydroxylacyl-CoA dehydrogenaseoxidizes secondary alcohol to ketoneOxygen-containing groupProduces NADH

  • Reactions of Beta Oxidation Acyl-CoA acetyltransferase (thiolase)Uses another CoAProduces Acetyl CoAAcyl CoA can go another round

  • Overall Per Beta Oxidation cycle1 FADH21.5 ATP1 NADH.2.5 ATP1 Acetyl CoA to Krebs3 NADH X 2.5 ATP / NADH7.5 ATP1 FADH2.1.5 ATP1 GTP..1.0 ATPTotal = 14.0 ATPDont use this values for FADH2 & NADH!!!!

  • Beta Oxidation on 16 C fatty Acid

  • Beta Oxidation on 16 C fatty Acid7 rounds of Beta oxidation (bottom numbers)Form 8 acetyl Co A (top numbers)

  • Beta Oxidation on 16 C fatty Acidtotals7 rounds of beta oxidation7 rounds X FADH2 X 1.5 ATP = 10.5 ATP round FADH27 rounds X NADH X 2.5 ATP = 17.5 ATP round NADH8 acetyl CoA8 Krebs8 Krebs X 3 NADH X 2.5 ATP = 60 ATP Krebs NADH8 Krebs X FADH2 X 1.5 ATP = 12 ATP Krebs FADH2 8 Krebs X GTP X 1 ATP = 8 ATPKrebs GTP1 ATP used to activate = - 1 ATP

    Use our orig values. Total107 ATP

  • Unsaturated Fat Metabolismspecial enzymes needed to convert cis bonds in fatty acids to trans bonds

  • Regulation of Fat MetabolismTransport is rate-limitingRegulation of carnitine acyl transferaseoff by fat synth productshigh NADH

  • Ketone BodiesStarvation causes accumulation of acetyl CoAnot enough carbohydrates to keep Krebs Cycle goingacetyl CoA forms acetoacetate, b-hydroxybutyrate, and acetone.http://www.biocarta.com/pathfiles/ketonebodiesPathway.asp

  • Diabetes and Ketone Bodies When there is not enough insulin in the blood and it must break down fat for its energy.Ketones build up in the blood and then spill over into the urine so that the body can get rid of them. Acetone can be exhaled through the lungs. This gives the breath a fruity odor. Ketones that build up in the body for a long time lead to serious illness and coma. (Diabetic ketoacidosis)

  • Comparison of Fat Metabolism per gram and CHO per gramFats provide about 9 kilocalories per gram and carbohydrates provide about 4 kilocalories per gram. Using nutritional units, that is 9 Calories/gram for fats and 4 Calories/gram for carbohydrates.CHO provide energy more quicklyFats are good fuel for endurance events, but not sprints



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