Question

A good resolution in ion exchange chromatography is obtained when the two proteins have a:

• A. large difference in binding affinity and large dispersion
• B. small difference in binding affinity and large dispersion
• C. large difference in binding affinity and small dispersion
• D. small difference in binding affinity and small dispersion

Hint:

In ion exchange chromatography, a large difference in binding affinity between proteins, even with large dispersion, helps ensure a clearer separation. Always consider the interplay between binding affinity and dispersion to optimize resolution.

Answer 1

The Correct Option is A

Step 1: Understand the concept of resolution in ion exchange chromatography.
Resolution in chromatography refers to the ability to distinguish between different substances. In ion exchange chromatography, proteins are separated based on their charge and interaction with the stationary phase, which is an ion-exchange resin. The resolution depends on how well the proteins are separated from each other.

Step 2: Analyze the factors affecting resolution.
Binding Affinity: The binding affinity refers to how tightly a protein binds to the stationary phase. A large difference in binding affinity between the proteins leads to a more distinct separation because the proteins will interact with the resin to different extents, resulting in different retention times.

Dispersion: Dispersion refers to the broadening of the protein bands as they move through the column. While large dispersion often means that the proteins elute over a broader time range, it can also improve resolution in some cases because the proteins might be well separated due to the substantial difference in their binding affinities, allowing for easier identification.

Step 3: Analyze the options

Option (1): Large difference in binding affinity and large dispersion
This is the correct option because a large difference in binding affinity ensures good separation between proteins, and even though the large dispersion might initially seem to reduce resolution, in this case, the difference in binding affinity can still lead to distinct separation of proteins in ion exchange chromatography.

Option (2): Small difference in binding affinity and large dispersion
This option is not ideal because although there is large dispersion, the small difference in binding affinity would not create a significant separation, making it difficult to resolve the proteins effectively.

Option (3): Large difference in binding affinity and small dispersion
This option would result in good resolution, but because large dispersion can sometimes aid in achieving even better separation in ion exchange chromatography, this combination is less optimal than the one with both large binding affinity difference and dispersion.

Option (4): Small difference in binding affinity and small dispersion
This option would result in poor resolution because both the small difference in binding affinity and the small dispersion would hinder the separation of the proteins effectively.