Questions: Dialysis during protein purification is a process to Dissolve insoluble proteins Concentrate proteins Remove high molecular weight substances Remove low molecular weight solutes such as salts

The answer is the last one: remove low molecular weight solutes such as salts.

Explanation for each option:

1. Dissolve insoluble proteins: This is incorrect. Dialysis is not used to dissolve insoluble proteins. It is a method used to separate molecules based on their size, typically to remove small molecules from a solution containing larger molecules.

2. Concentrate proteins: This is incorrect. While dialysis can sometimes result in a slight concentration of proteins due to the removal of solvent, its primary purpose is not to concentrate proteins. Other methods, such as ultrafiltration, are more commonly used for concentrating proteins.

3. Remove high molecular weight substances: This is incorrect. Dialysis is designed to retain high molecular weight substances (like proteins) inside the dialysis bag while allowing low molecular weight substances to diffuse out.

4. Remove low molecular weight solutes such as salts: This is correct. Dialysis is commonly used to remove small molecules, such as salts, from a solution containing larger molecules, such as proteins. The dialysis membrane allows the small molecules to pass through while retaining the larger molecules.

Summary: Dialysis during protein purification is primarily used to remove low molecular weight solutes such as salts from a solution containing larger molecules like proteins.