6 question 7 total points 40 a solution made by

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Question #7. Total points =40
A solution made by mixing 50 mL of 2.0 M K
2
HPO
4
and 25 mL of 2.0 M KH
2
PO
4
. The solution
is diluted to a final volume of 200 mL. What is the pH of the final solution? pKa of KH
2
PO
4
6.82; pKa of K
2
HPO
4
=12.38.
=
7

Question #8. Total points =4X 20=80
You are trying to purify a protein (protein A) of 350 amino acids in length (average molecular
weight of an amino acid is 110 Da). The oligomeric state, PI, enzymatic activity and ligand
binding properties of this protein is listed below. Protein A is present in a mixture of several
other monomeric proteins of molecular weights ranging from 75,000 to 85,000 Da. Explain the
following (2-4 sentences for each).
Protein A
PI 5.4
Size (MW) 82,000
Oligomeric property Dimer
Enzymatic activity Adds phosphate to
other proteins
Ligand binding Binds metal ion
a. Which ion exchange chromatography would you prefer to use and why?
b. Explain if the size exclusion chromatography can be used as a separation step. c. Explain if affinity chromatography can be used as a separation step. d. Explain if hydrophobic chromatography can be used as a separation step.
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