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Before describing the structure and mechanism of action of a protein, it must first be subject to purification procedure. Protein purification is a set of processes in which one or a small number of proteins are purified from a complex compound that may be a complete cell, tissue, or organism. Understanding the functions, structural properties, and interactions of the protein are directly related to the degree of purity of the protein of interest. In the purification process, the protein and non-protein parts are separated. The biggest challenge is when the protein must be separated from other proteins. The purification procedure of an unknown protein is usually depends on the size, physicochemical properties, binding affinity, and biological activity. The end product of the purification process is called protein isolate. The protein purification process usually involves filtration and one or more chromatographic steps. Chromatography is a useful method for acquiring very pure protein for using in very accurate experiments. Therefore, by purifying the desired molecule, it can be used in various industries, such as medicine.