Question

Two-dimensional gel electrophoresis carries out protein based on

• A. Mass and hydrophobicity
• B. Mass
• C. Charge and mass properties
• D. Disulphide bonding

Hint:

Remember the order and principle of 2D-PAGE: 1st dimension is IEF (separates by charge/pI), and the 2nd dimension is SDS-PAGE (separates by mass). The combination gives much higher resolution than either technique alone.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Two-dimensional gel electrophoresis (2D-PAGE) is a powerful technique used to separate complex mixtures of proteins. It involves two sequential separation steps, each based on a different physicochemical property of the proteins.
Step 2: Detailed Explanation:
The two dimensions of separation are:
First Dimension: Isoelectric Focusing (IEF). In this step, proteins are separated along a pH gradient based on their isoelectric point (pI). The pI is the pH at which a protein has no net electrical charge. Proteins migrate through the pH gradient until they reach their pI, where they stop moving. This first step separates proteins based on their charge.
Second Dimension: SDS-Polyacrylamide Gel Electrophoresis (SDS-PAGE). After IEF, the gel strip containing the separated proteins is placed on top of a standard SDS-PAGE slab gel. In this step, the proteins are coated with the detergent sodium dodecyl sulfate (SDS), which imparts a uniform negative charge. They are then separated based on their molecular mass (size), with smaller proteins migrating faster through the gel.
Therefore, the overall technique separates proteins based on their charge properties in the first dimension and their mass properties in the second dimension.
Step 3: Final Answer:
2D-PAGE separates proteins based on charge and mass.