The process of fatty acid anabolism is an endergonic process and fatty acid catabolism is quite endergonic process. Compare the amount of ATPs required for the biosynthesis of stearic acid (18C saturated fatty acid) with the amount of ATPs produced by the β-Oxidation of the same fatty acid. Which of these two processes is most thermodynamically favorable process?
Answers
Answer:
1.
Synthesis takes place in the cytosol, in contrast with degradation, which takes place primarily in the mitochondrial matrix.
2.
Intermediates in fatty acid synthesis are covalently linked to the sulfhydryl groups of an acyl carrier protein (ACP), whereas intermediates in fatty acid breakdown are covalently attached to the sulfhydryl group of coenzyme A.
3.
The enzymes of fatty acid synthesis in higher organisms are joined in a single polypeptide chain called fatty acid synthase. In contrast, the degradative enzymes do not seem to be associated.
4.
The growing fatty acid chain is elongated by the sequential addition of two-carbon units derived from acetyl CoA. The activated donor of twocarbon units in the elongation step is malonyl ACP. The elongation reaction is driven by the release of CO2.
5.
The reductant in fatty acid synthesis is NADPH, whereas the oxidants in fatty acid degradation are NAD+ and FAD.
6.
Elongation by the fatty acid synthase complex stops on formation of palmitate (C16). Further elongation and the insertion of double bonds are carried out by other enzyme systems.