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β- Oxidation of fatty acids ط Transport of fatty acids into mitochondria ط β- Oxidation of fatty acids ط steps and energetic D4 381-7 . Introduction 1. FAs consist of 1 CH3 methyl end, Carbon chain, COOH carboxyl end
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β-Oxidation of fatty acids ط Transport of fatty acids into mitochondria ط β- Oxidation of fatty acids ط steps and energetic D4 381-7
Introduction 1. FAs consist of 1 CH3 methyl end, Carbon chain, COOH carboxyl end 2. Short chain SC-FAs (>8C), medium chain MC-FAs (8-12C), Long Chain LC-FAs (<12C) 3. Saturated FAs (straight chain), Unsaturated FAs (has == double bond; cis same side H & trans opposite side H) 4. Odd chain FAs consist of odd number of carbon chain
β-FAO (for saturated LC- & MC-FA, 1st cut between C2 & C3) fig9.19 End Retic / cytosol: FA AACoA S-ase (–2ATP/CoA) FACoA outer mitoch memb: FACoA + Carnitine CPT1 (+CoA) FACarnitine inner mitoch memb: FACarnitine T-lase FA + Carnitine inner mitoch memb: FA CPT2 (–CoA) FACoA mitoch matrix: FACoA ACoADH (+FADH2) trans-2ECoA ECoAH-tase (–H2O) L-HACoA L-HACoA HACoADH (+NADH) β-KACoA β-KACoA β-KACoA T-alse (+CoA) FACoA (–2C) + ACoA (to TCA cycle) * one turn produce 5 ATP (2 from FADH2 & 3 from NADH) * one ACoA enters TCA cycle produce 12 ATP * complete oxid of 16C FA chain (Palmitoyl Acid) produce 129 ATP (2 ATP used for entery into mitoch) * Reactions regulated by ACoA, cofactors, Carnitine
Oxidation of fatty acids and clinical aspects ط Saturated and unsaturated fatty acid oxidation ط Oxidation of odd number fatty acids ط α- oxidation and ω-oxidation of fatty acids ط Clinical correlation : Refsum’s disease Genetic deficiencies in Carnitine transport D4 381-7
Unsaturated FAO (for LC-FA, to overcome == bouble bonds) fig9.22 LCoA => β-Oxid (+3CoA) => cis·3ECoA ECoA I-asetrans·2ECoA => β-Oxid (+CoA) => cis·4ECoA cis·4ECoA ACoADHtrans·2-cis·4ECoA DECoA R-ase (–NADPH) trans·3ECoA trans·3ECoA ECoA I-asetrans·2ECoA => β-oxid (+5ACoA) α-FAO (1st cut between C1 & C2) Hydroxylation of saturated SC-FA (Mitoch & End Retic) Hydroxylation of LC-FA only for Sphingolipids ω-FAO (at methyl end) Hydroxylation of saturated MC-FA (in End Retic) and for Hydroxy FA (phospholipids) Odd-Chain FAO (modification of α-oxid) same as from AA => α-oxid => PCoA => carboxylation => MMCoA => conversion => SCoA
Clinical Correlation of FAOcc.9.4 Genetic deficiency in Carnitine or CPT cause mild-recurrent muscle cramps to severe weakness & death · Carnitine Primary Deficiency: o No LC-FAO (heart / muscle) o Diagnosed by low plasma carnitine o Treated by Dietary Carnitine · Carnitine Secondary Deficiency: o Accumulation of FAcOA / FACarnitine plasma lead to excretion in urine o Drainage of body from carnitine lead to impaired tissue uptake of carnitine o Cannot treat with Dietary carnintine · CPT genetic deficiency: o Most common is deficiency of CPT2 o Lead to muscle weakness during prolonged exercise o Fatal for children (hypoketotic, hypoglycaemia, hyperammonemia) o Treated by avoiding starvation and use low LC-FA in diet ± dietary MC-TG (carnitine independent)