Structural Biochemistry/Proteins/Purification

General Information
Protein Purification  is the process of separating proteins for individual analysis. Protein purification is the second step of studying proteins, the first being the process of an assay. An assay is a procedure to measure the activity enzyme activity thus confirming the presence of the protein or proteins in interest. Popular assays include Western Blotting and ELISA(Enzyme-linked immunosorbent assay). Before the purification process, Cell Disruption is utilized to homogenize the cell's content. After the cell has been opened up, the process of purifying proteins from one another and the other organelles can be approached in several different methods. Protein mixtures are normally separated multiple times, each based on a different property, such as:
 * Solubility
 * Size
 * Molecular Weight
 * Charge
 * Binding affinity

The intended reason for purifying a specific protein governs the level and degree of protein purification. At times, a sample of protein that is only moderately purified suffices for its intended application; however, other situations require a higher degree of purification, especially if the fundamental ambition is to study the characteristics and tendencies of the specific protein in interest. By considering solubility, size, molecular weight, charge, and binding affinity, the goal of the scientist that conducts protein purification is to find a level of purification necessary and create a protein yield that is ample for further research and application. This means using the fewest steps in order to keep the yield high, as each protein purification step incurs a degree of product loss. Therefore two factors serve as obstacles in protein purification: yield and purification level. The main goal of each protein purification project falls under two categories: analytical (for studying and research purposes) and preparative (for production and creation of commercial products).

There are many methods of purification including:
 * Differential Centrifugation
 * Salting Out
 * High Pressure Liquid Chromatography
 * Gel-Filtration Chromatography
 * Ion-Exchange Chromatography
 * Affinity Chromatography
 * Hydrophobic Interaction Chromatography
 * Fast Protein Liquid Chromatography
 * Isoelectric Focusing
 * Dialysis
 * The_Miniaturization_of_PFK-1_Purifications