Organic Chemistry III
	Professor Carl C. Wamser
	Quiz 27	Chem 336 - Spring 2005

1. (2 points) Write the structure of the tripeptide Lys Tyr Pro as it would be at pH 7.
It is not necessary to show the stereochemistry at the alpha positions.

2. (2 points) Show the reagents that would be needed to prepare Phe by each of these routes:

a)

b)

3. (3 points) You have a peptide synthesizer with five bottles labeled as below. Show the order in which you would use these to prepare the dipeptide Met Val .

A = Met ; B = Val ; C = BOC ; D = DCC ; E = HBr

A, then C, then D, then B, then E

4. (3 points) Identify the unknown hexapeptide based on the data below.

Complete hydrolysis gives equal moles of Glu , Leu , Lys , Phe , Tyr , Val .
Edman’s reagent releases Tyr.
Carboxypeptidase releases Glu .
Chymotrypsin releases Tyr , Glu , and a tetrapeptide A .
Trypsin releases two tripeptides, B and C .
The N-terminus of C is found to be Val .

Tyr-Leu-Lys-Val-Phe-Glu