Question

Given the following table of protein information, what is the order (first to last) in which you would assume proteins would come off a gel filtration (size exclusion chromatography) column?
Molecular Wt. (da) pI(ioselectric point
Protein 1 9,000 7.1
Protein 2 49,000 6.3
Protein 3 25,000 6.0
a. Protein 1, Protein 2, Protein 3
b. Protein 3, Protein 2, Protein 1
c. Protein 2, Protein 1, Protein 3
d. Protein 2, Protein 3, Protein 1
e. Protein 1, Protein 3, Protein 2
Please justify your answer

Answer 1

Ans. In the size-exclusion chromatography separation technique, the largest molecule (large in size or here, molecular mass) elute first and the smallest particle elute last.

So, order of elution (first to last) is – Protein 2 (49000) , Protein 3 (25000), Protein 3 (9000)

So, correct option is- D

# In pI of the proteins to be considered, the pH of elution buffer must be mentioned. Since the pH of elution buffer is NOT mentioned, it’s assumed that the elution is solely based on size of molecules.