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: Overview:
Two-dimensional gel electrophoresis (2D-PAGE) is a method for separating complex protein mixtures. It uses two successive separation steps, each exploiting a different physical property of the proteins.
Step 2: Method:
The two separation dimensions are:
First Dimension: Isoelectric Focusing (IEF). Proteins are separated by isoelectric point (pI) along a pH gradient. The pI is the pH where a protein has no net charge. Proteins migrate until they reach their pI, where movement stops. This step separates proteins by charge.
Second Dimension: SDS-Polyacrylamide Gel Electrophoresis (SDS-PAGE). Following IEF, the gel strip with separated proteins is placed on an SDS-PAGE gel. The detergent sodium dodecyl sulfate (SDS) coats the proteins, giving them a uniform negative charge. They are then separated by mass (size), with smaller proteins moving faster.
In summary, the technique separates proteins by charge in the first dimension and by mass in the second.
Step 3: Conclusion:
2D-PAGE separates proteins by charge and mass.