Question - An unknown protein (i.e., not BSA) binds to Carboxy Methyl (CM) -cellulose (pKa 4) at pH 7.0.
The loading buffer is 0.1M imidazole pH7.
a. Draw the two structural forms of the CM functional group. (Hint: see second page).
State the charge on the form which predominates at pH 7.0.
b. What is the charge on the protein at pH 7.0? Explain.
c. How can the bound protein be eluted from this particular resin?
Explain using 2 different methods describing the type of buffer used for each elution.
d. What can you conclude about the pI of the bound protein? Explain.