BIOCHEMISTRY - L. Stryer - 1984

VOLUME 2

PART II GENERATION AND STORAGE OF METABOLIC ENERGY

CHAPTER 18. AMINO ACID DEGRADATION AND THE UREA CYCLE

QUESTIONS AND PROBLEMS

1. Name the a-oxo acid formed by the Transamination of each of the following Amino Acids:

a) Alanine,

b) aspartate,

c) glutamate,

d) leucine,

e) phenylalanine,

f) Tyrosine.

2. Write the overall equation for The conversion of aspartate into glucose via oxaloacetate. Indicate the Coenzymes involved in these reactions.

3. Write the equation for the equilibrium conversion of aspartate to oxaloacetate via fumarate.

4. Analyze The Mechanism of the conversion of L-methylmalonyl-CoA to succinyl-CoA catalyzed by L-methylmalonyl-CoA mutase.

a) Propose an experiment to distinguish between the migration of the —COO- group and the —CO—S—CoA group in this reaction.

b) In reality, the —CO—S—CoA group migrates. Now propose an experiment to determine whether this group transfer is intermolecular or intramolecular.

c) What is The Significance of the observation that when the mutase reaction is carried out in tritiated Water, no tritium is incorporated into succinyl-CoA?

5. Pyridoxal phosphate stabilizes carbanion intermediates by functioning as an electron sink. What other prosthetic group catalyzes reactions in the same manner?



Last update: 06/08/2026

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