Suzhou protein purification system: protein purification methods and their advantages and disadvantages (1)

Hello everyone, today Suzhou Protein Purification System Manufacturer Suzhou Sepure Instrument Co., Ltd. talks about protein precipitation with protein purification methods.

Protein is soluble in water because of the hydrophilic amino acids on its surface. If the ionic strength of the solution is particularly high or low at the isoelectric point of the protein, the protein tends to precipitate out of the solution.

Ammonium sulfate is a commonly used salt for protein precipitation, because it has good solubility in cold buffer, and cold buffer helps maintain the activity of the target protein. Ammonium sulfate fractionation is often used as the first step in laboratory protein purification. It can preliminarily extract proteins and remove non-protein components. Proteins are more stable in ammonium sulfate precipitation, and intermediate products can be stored in this state for a short period of time. At present, protein purification mostly uses this method for crude separation.

There are still some problems in the ammonium sulfate precipitation method in large-scale production. Ammonium sulfate is very corrosive to stainless steel appliances. Other salts such as sodium sulfate do not have this problem, but its purification effect is not as good as ammonium sulfate. In addition to salting out, the protein can also be precipitated with polymers such as PEG and antifreeze. PEG is an inert substance that has the same stabilizing effect on protein as ammonium sulfate, and gradually increases the concentration of PEG in the cold protein solution under slow stirring Protein precipitation can be obtained by centrifugation or filtration, and the protein can be stored in this state for a long time without damage.

Protein precipitation is not a very good method for protein purification, because it can only achieve a few times the purification effect, and we need thousands of times of purification before reaching the goal. The advantage is that the protein can be released from the culture medium and cell lysate mixed with protease and other harmful impurities.

The above is the protein precipitation method of protein purification, provided by Suzhou Sepure Instrument Co., Ltd.