Question

Which method would work best to isolate protein Z from this mixture of proteins?

Protein       M.W.           pI

X               20,000         6.1

Y               75,000        9.1

Z              110,000        4.6

Answer choices:

a. cation exchange at pH=7

b. size-exclusion P100 gel (5,000-100,000 MW fractionation range)

c. anion exchange at pH=7

d. size-exclusion P60 gel (3,000-60,000 MW fractionation range)

Answer 1

Solution:

Option B

Proteins are best separated or isolated from gel filtration technique. Here, smaller molecular masses containing proteins are adsorbed and the protein having highest molecular weight is easily pass through the column.

Thus, 5000-100000 MW containing proteins are adsorbed and 110000 MW protein (Z) is separated.