If fatty acid synthesis and β oxidation were to proceed simultaneously, the two processes would constitute a futile cycle, wasting energy. We noted earlier that β oxidation is blocked by malonyl-CoA, which inhibits carnitine acyltransferase I. Thus, during fatty acid synthesis, production of the first intermediate, malonyl-CoA, shuts down β oxidation at the level of a transport system in the inner mitochondrial membrane. This control mechanism illustrates another advantage of segregating synthetic and degradative pathways in different cellular compartments.
举一反三
- Synthesis of fatty acids from acetyl CoA A: need NADPH B: need NAD+ C: produce malonyl CoA in the first step D: occur in mitochondria E: It's the reverse reactions of fatty acid oxidation
- During long term starvation, the energy in brain mainly come from A: glucose oxidation B: ketone bodies oxidation C: lactate oxidation D: amino acid oxidation E: fatty acid oxidation
- During long term starvation, the energy of brain mainly come from A: glucose oxidation B: fatty acid oxidation C: ketone bodies oxidation D: lactate oxidation E: amino acid oxidation
- The inhibition of carnitine acyltransferase I by malonyl-CoA ensures that the oxidation of fatty acids is inhibited whenever the liver is amply supplied with glucose as fuel and is actively making triacylglycerols from excess glucose.
- Besides acetyl CoA, the odd carbon atom fatty acid after β-oxidation produces acetyl CoA.（）