You must reference your postings. Chemical structures, equations and figures are essential.
1. Discuss how many ATP would be synthesized from the complete oxidation of stearic acid or linoleic acid to carbon dioxide and water.
a) Discuss how many ATP would be synthesized from the complete oxidation of stearic acid to carbon dioxide and water.
b) What additional steps are required to oxidize linoleic acid (a polyunsaturated fatty acid)? Include relevant chemical structures and reactions.
c) Explain why the complete oxidation of linoleic acid leads to fewer ATP than the oxidation of stearic acid.
2. Discuss how the results of Franz Knoop’s experiments led to the formulation of the β-oxidation pathway
a) Discuss the experimental details. Chemical equations and structures are essential.
b) Discuss the results of his experiments. What was surprising about these results?
c) What conclusions did he draw?
3. Discuss how hypoglycin (an unusual amino acid found in the unripened fruit of the akee tree) acts as a mechanism-based inhibitor of acyl-CoA dehydrogenase.
a) What is a mechanism-based inhibitor? How is it different from a transition state analog?
b) How is hypoglycin metabolized in the cell? What compound is formed? Include relevant chemical structures and reactions.
c) How does the compound formed in part b inhibit acyl-CoA dehydrogenase? Include relevant chemical structures and reactions.
d) Compare the mechanism of inhibition of β-oxidation by hypoglycin A with the mechanism of inhibition of the TCA by fluoroacetate.
4. Compare and contrast the last three steps of the TCA with the first three steps of β-oxidation. Include relevant chemical structures and reactions.
a) How are these reactions similar in terms of substrates and products, sequence of reactions, involvement of coenzymes?
b) How are they different in terms of fate of the electrons, stereochemistry of the reactants and products…?
c) Compare and contrast the mechanisms of these three steps.
5. Discuss the conversion of propionyl CoA to succinyl CoA in relation to both amino acid oxidation and oxidation of fatty acids with an odd-number of carbons. Include relevant chemical structures and reactions.
a) Why is propionyl CoA formed in the oxidation of fatty acids with an odd-number of carbons?
b) What is the sequence of reactions that converts propionyl CoA to succinyl CoA? Be sure to include the names of the enzymes and the chemistry of each step.
c) Discuss each step of the conversion mechanistically, including the involvement of the coenzymes.
d) What is unusual about the third step of this reaction? What coenzyme is essential and what is unusual about its mechanism of action?
6. Discuss the toxic effects of the ammonium ion and excess bicarbonate ion.
a) What is the effect of high concentrations of NH4+ in the bloodstream?
b) What are the two reasons NH4+ is so toxic to the brain?
c) Why can the urea cycle also be considered as a bicarbonate ion disposal mechanism? Why is that important?
7. Discuss the two roles of N-acetylglutamate in the urea cycle. Include relevant chemical structures and reactions.
a) What is the regulatory function of N-acetylglutamate in the urea cycle?
b) What is the other role of N-acetylglutamate in relationship to the urea cycle?
c) Glutamate is the precursor for N-acetylglutamate. How is glutamate involved in the connection between the urea cycle and the CAC?
