Lipid Metabolism

• ___ occurs in the cytosol

  Fatty acid activation
• ___ occurs in the mitochondria and peroxisomes

  beta oxidation
• Products of beta oxidation

  Acetyl-CoA, NADH, FADH2 ; Propionyl CoA (for odd numbered C fatty acids)
• Rate-limiting step in beta oxidation

  Translocation of fatty Acyl CoA from the cytosol to the mitochondria
• Step 1: ATP-dependent acylation to form fatty acyl-CoA catalyzed by ___

  acyl-CoA synthetases (thiokinases)
• Step 2: Acyl coA to ___ by specific carrier proteins

  mitochondria
• enzyme: coA to carnitine

  CPT1
• enzyme: carnitine to coA (after entrance)

  CPT2
• ___ repeatedly cleave two carbon units from the carboxyl end of the acyl CoA molecule

  Four reactions
• Step 3-1: Oxidation (Acyl CoA to trans-enoyl CoA through ___)

  Acyl CoA dehydrogenase
• Step 3-2: Hydration (trans-enoyl CoA to L-B-hydroxyacyl CoA through ___)

  Enoyl CoA hydratase
• Step 3-3: Oxidation (L-B-hydroxyacyl CoA to B-Ketoacyl CoA through ___)

  B-hydroxyacyl CoA dehydrogenase
• Step 3-4: Thiolysis (B-Ketoacyl CoA to Acyl CoA + Acetyl CoA through ___)

  Thiolase
• Step 3-4: Thiolysis (What is required to conduct this process?)

  CoA-SH
• Beta-Oxidation for UFA: (1) Epimerase – ___

  Changes D configuration to an L configuration
• Beta-Oxidation for UFA: (2) Cis–trans isomerase – ___

  Produces a trans-(2,3) double bond from a cis-(3,4) double bond
• ATP Yield of Palmitate

  129 ATPs
• ___ are the water-soluble molecules containing the ketone group that are produced by the liver from fatty acids

  Ketone bodies
• Involves the synthesis of ketone bodies from acetyl CoA

  Ketogenesis
• Site of Ketogenesis


  mitochondria of the liver
• The three ketone bodies produced in ketogenesis are:

  ⮚Acetoacetate

  ⮚β-hydroxybutyrate

  ⮚Acetone
• Ketogenesis 1: Two acetyl CoA molecules combine to produce acetoacetyl CoA 


  First Condensation (thiolase)
• Ketogenesis 2: Acetoacetyl CoA reacts with a third acetyl CoA and water to produce 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) and CoA–SH


  Second Condensation (HMG-CoA synthase)
• Ketogenesis 3: HMG-CoA is cleaved to acetyl CoA acetoacetate


  Chain Cleavage (HMG-CoA lyase)
• Ketogenesis 4: Acetoacetate is reduced to β-hydroxybutyrate


  Hydrogenation (D-B-hydroxybutyrate dehydrogenase)
• Ketogenesis Step 4: Acetoacetate to acetone through ___

  non-enzymatic decarboxylation
• act by inhibiting HMG-CoA reductase and thereby reducing cholesterol synthesis

  statins
• ___ are produced in the intestine and conduct fats to the liver, skeletal muscles and adipose tissue via the lacteals

  Chylomicrons
• ___ carry cholesterol from the liver to the body

  LDLs
• ___ carry excess cholesterol back to the liver for disposal (good)

  HDLs
• ___ and ___ exist as transitional forms between chylomicrons and LDLs

  VLDLs and IDLs
• Chylomicrons have high ___

  TAGs
• LDLs have high ___


  cholesterol
• HDLs have high ___

  proteins