Download The pathway from “activated acetic acid” to fatty acids and terpenes

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The pathway from “activated
acetic acid” to fatty acids and
terpenes
Feodor Lynen
(The fatty acid cycle)
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Feodor Lynen, Nobel Prize 1964, Fatty Acid Metabolism
Triglycerides are also stored in muscle
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Lipases hydrolyze triglycerides
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Fatty acid degradation – standard sequence
Acyl CoA Synthase
Adenylation of FA drives formation of thioester
Essentially 2 ATPs hydrolyzed
Amino acids activated in the same way for
attachment to tRNA
Mitochondrial outer membrane
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Fatty acyl spiral
Acyl CoA dehydrogenase
L-3-hydroxyacyl CoA reductase
Enoyl CoA hydratase
β-keto thiolase
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Odd numbered FAs yield:
Ketone bodies are formed from acetyl CoA when
fat metabolism predominates-
Balance of carbohydrate and fatty acid metabolism: AcetylCoA can only enter
CA cycle by reacting with oxaloacetate. Need pyruvate from glucose to keep
oxaloacetate at sufficient levels. Formation of ketone bodies.
Discovered HMG-CoA cycle-intermediates in
synthesis of terpenes and cholesterol (like citric acid cycle). See Ch 26, Fig. 26.8
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Fatty Acid Synthesis-Intermediates
Attached to acyl carrier protein
Fatty acid synthesis
Formation of Malonyl CoA by Acetyl CoA carboxylase
Biotin-enzyme +ATP+HCO3CO2-biotin+acetyl CoA
CO2-biotin-enzyme plus ADP +Pi
malonyl CoA + biotin enzyme
Committed step in FA biosynthesis
Acetyl CoA Carboxylase
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Pyruvate dehydrogenase is irreversible and so is
Pyruvate kinase
Need to make phosphoenolpyruvate from oxaloacetate to
reverse glycolysis for gluconeogenesis
Variations on a theme: ketide synthesis
(Also peptides)
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