SDS-PAGE vs. native PAGE vs. isoelectric focusing
A researcher wants to separate a mixture of proteins based only on molecular mass. Which technique is best?
Answer A: explanation for every choice
A
Correct. SDS denatures proteins and coats them with a roughly uniform negative charge per unit mass, so migration depends on size.
B
Native PAGE separates by a combination of size, shape, and charge.
C
Isoelectric focusing separates proteins by their isoelectric point (pI).
D
Ion-exchange chromatography separates by net charge.
TakeawaySDS removes differences in charge and shape, leaving mass.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb17.