If a protein subunit has a molecular weight of 50 kDa, how would its relative mobility compare to a 25 kDa subunit in SDS-PAGE?

• A. The 25 kDa subunit will have higher mobility.
• B. The 50 kDa subunit will have higher mobility.
• C. Mobility cannot be determined from molecular weight.
• D. Both subunits will have the same mobility.

Answer: (A)