What is the purpose of performing a dialysis step after GFP purification?

The dialysis step after GFP purification primarily serves the purpose of removing excess salts and small molecules from the purified GFP solution. During the purification process, various salts and small molecules may be present, which can interfere with subsequent experiments or applications of the protein. Dialysis utilizes a semipermeable membrane that allows smaller molecules, such as salts and other impurities, to diffuse out of the protein solution while retaining the larger GFP molecules. This step helps ensure that the final product is of higher purity and suitable for further use, such as in biochemical assays or structural studies.

While concentrating the GFP solution, increasing yield, and enhancing solubility are important factors in protein purification, the primary function of dialysis in this context is specifically aimed at the removal of unwanted small contaminants, making purified GFP more effective for subsequent applications.