How do I choose a method for protein purification?

There are several factors to consider when choosing a method for protein consideration. Some factors include the characteristics of the protein, the desired use of the protein, the quantity of protein necessary, and time taken during the purification. The characteristics of a protein include its size, whether it is hydrophobic or hydrophilic, charge, and solubility. For example, for proteins that are small and hydrophilic, size exclusion chromatography may be utilized due to the ability of all molecules being small enough to fit completely into all regions of the pore. In contrast, for large and hydrophobic proteins, affinity chromatography would be more efficient. The second factor to consider is the quantity of the protein. The quantity required will determine the appropriate purification method. Affinity chromatography may be appropriate for small experiments, and ion exchange chromatography may be suitable for larger experiments. The desired use of the protein is another factor as it will determine the amount of purity required. For example, some enzymatic assays require high levels of purity while protein assays like Western blotting may require lower levels of purity. Lastly, there are different times required for carrying out each purification, and some types may be more time-consuming than others.