C483 Review Problem Set for Week April 21-25
1. Below is an outline of the degradation of isoleucine. ALL of the reactions of this
pathway are similar (use the same chemistry, cofactors, enzyme types and
cosubstrates) to ones you have seen. Going reaction by reaction, fill in the missing
reactants/products/cofactors (i.e. TPP, or biotin, or PLP, etc.) for each step. State
what reactions in primary metabolism these reactions are similar to.
2. Gelatin, which is largely derived from collagen, has a PDCAAS of about zero.
What does a score of zero tell you?
What does this say about collagen as a source of dietary amino acids?
Does this mean collagen is useless as an amino acid source?
3. What are the essential amino acids? Why are sulfur-containing amino acids
lumped together?
4. What is meant by a conditional essential amino acid?
5. How does roundup (glyphosate) work?
6. What is the role of vitamin B-12 in the active methyl cycle?
7. THF may contain and transfer methyl groups at three oxidation states. Draw the
cofactor when it contains these three moieties.
8. Why should phenylketonuriacs avoid aspartame? What is the structure of
aspartame (you will have to look this up), and what is it degraded into?