Protein purification Service

Protein purification is an important technology in the field of biological research.To study a specific protein, it is necessary to separate and purify it from the organism.Protein purification mainly uses the similarity and difference between different proteins.ni

The purification of protein can be roughly divided into two stages: coarse separation stage and fine purification stage.In the stage of rough separation, the target protein and other cell components such as RNA and DNA are separated, and the common method is ammonium sulfate precipitation.The purpose of the fine purification stage is to distinguish the target protein from other proteins of the size and physicochemical properties. The commonly used methods are gel filtration chromatography, ion exchange chromatography, hydrophobic chromatography, affinity chromatography, etc.

Gel filtration (also known as exclusion chromatography or molecular sieve) is a method for separating proteins from mixtures based on molecular size.There are differences in the shape and molecular size of different proteins, and the ability of diffusion into particles with specific pore size is also different. Large protein molecules will be eluted first, and the smaller the molecule, the later the elution, so as to achieve the purpose of protein separation.Generally speaking, the thinner and longer the gel filtration column is, the better the purification effect is.

Ion exchange chromatography is a kind of technology for protein separation and purification according to different charges on the surface of protein. Under certain conditions, charged amino acid residues can be reversibly combined with cation exchange column or anion exchange column. When they are eluted with buffer solution which changes pH or gradually increases ionic strength, substances with different charges are eluted in turn, so as to achieve the separation effect.

Affinity chromatography is a technology of protein purification by using the reversible binding of biomacromolecules with some corresponding molecular specificity.We can use the specific adsorption between ligand and molecular biology to separate proteins, or we can add labels on proteins, and use the specific binding between labels and ligands to purify proteins.

Hydrophobic interaction chromatography is a kind of chromatography method which uses the different hydrophobic force between the hydrophobic group of sample molecule and the hydrophobic ligand of chromatography medium to separate.The hydrophobic can be used as a weak to strong component separation in turn with eluates of high to low ionic strength.