Problem Set 5
1. Serine has pKa's of 2.21 and 9.15.
a. Draw the three forms of
serine that could be present at various pH's. Show all bonds, atoms, and
charges.
b. Draw the structure of
serine that is most prevalent at physiological pH.
c. Draw the structure of
serine that would be prevalent for a pH range of 1-2 (stomach).
d. For a pH of 10.15, draw
and calculate the ratio of the two most prevalent forms of serine.
2. Lysine has pKa's of 2.18, 8.95, and 10.53 (side chain).
a. Draw the structure of
lysine that is most prevalent at physiological pH.
b. Draw and calculate the
ratio of the two most prevalent forms of lysine at a pH of 4.0.