Question

While separating the protein using polyacrylamide gel electrophoresis, the major ions playing an important role in stacking the protein are:
i. Glycine of the running gel buffer
ii. Chloride ion
iii. The protein itself
Which of the following is correct?

• A. ii moves faster than i, and i moves faster than iii
• B. iii moves faster than i and ii
• C. i moves faster than ii and iii
• D. ii moves faster than iii and iii moves faster than i

Hint:

In SDS-PAGE, stacking occurs due to differences in ion mobility between the leading ion (chloride) and trailing ion (glycine).

Answer 1

The Correct Option is D

1. Chloride ions (ii) move fastest because of their small size and high mobility.
2. Proteins (iii) move next, followed by glycine (i), which is slower due to its zwitterionic form at the stacking pH.