Suppose you have two genetic variants of a large protein that differ only in that one contains a histidine (side chain pKa = 6.0) when the other has a valine (uncharged side chain).1. Which would be better for separation: gel electrophoresis or isoelectric focusing?A. Gel electrophoresis. B. Isoelectric focusing.2. What would you choose for the separation?A. At a pH of 6.0.B. At a pH above 6.0.C. At a pH below 6.0.D. At any pH value.

1. The correct option is B: Isoelectric focusing

2. The correct option is A: At a pH of 6.0

Explanation:

1. Gel electrophoresis is a technique used to separate proteins on the basis of size. Since these two proteins are of similar size (or molecular weight), it will prove to be ineffective to achieve the desired result.

2. Since valine has an uncharged side chain, it will not be affected by pH value so it needs to be maintained at the value where it does not exert direct influence on the protein with histidine.

not: both offer magnification to the atomic level.