Chem 336 - Spring 2002
Organic Chemistry III
Dr. Carl C. Wamser
1. (3 pts) Write a structure for the dipeptide GlyArg as it would appear at pH 7. Include stereochemistry.
2. (2 pts) Illustrate H-bonding interactions using the side chains of Tyr and His (in their neutral forms).
3. (3 pts) Show the structures of all of the components expected after complete hydrolysis of the dipeptide IleAsn in strong acid (final pH 1). Stereochemistry is not required.
4. (2 pts) Identify the unknown pentapeptide from the following data.
Complete hydrolysis gives one equivalent each of Cys, Glu, Phe, Pro, Val.
Chymotrypsin cleavage gives a dipeptide containing Phe and Pro and a tripeptide.
Treatment of the tripeptide with Sanger’s reagent labels Glu, and treatment with Edman’s reagent releases Glu followed by Cys.
Pro Phe Glu Cys Val
