PROBLEM SET 22A-Tryptophan. Stage1. Removal of the Side Chain


1. Tryptophan has the following structure:

What can you conclude about the ring?

2. Using transamination, oxidative decarboxylation and opening the imidazole ring, in no particular order, construct a tentative map for stage 1  of tryptophan catabolism.

3. What predictions can you make from your tentative map.

4. Look for the enzymes that catalyze the reactions you have written and revise your map.

5. Write a detailed mechanism for the reaction of kynurenine with PALP.

What predictions can you make about the next reaction?

6. Check the prediction that there is a PALP-enzyme that uses water  to cleave the side chain of kynurenine and produce either pyruvate or alanine depending on which tautomer it selects for hydrolysis.

7. The enzyme, 3-hydroxykynurenine monooxygenase (EC has been reported in Homo  sapiens.  White a mechanism for the reaction.

8.  Construct an final map for removal of the side chain from tryptophan.








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