(a)[2]
Using the Data Booklet, sketch the structure of the dipeptide val-lys. The peptide bond should be shown in displayed form.
(b)[5]
The isoelectric point is the pH at which an amino acid is present as a zwitterion. Valine has an isoelectric point of 6.0 and lysine has one of 9.8. A mixture containing the dipeptide, val-lys, and its two constituent amino acids, valine and lysine, was separated by electrophoresis in a buffer at pH 6.0. On the electrophoresis paper diagram, draw and label three spots to show the expected position of each species after electrophoresis. Explain your answer.