ABSTRACT
The enzymatic activity could be readily assayed in the homogenate from a rat liver but disappeared as the purification proceeded. The strategy for the purification of a protein is tailored to the particular problems faced in each instance. The goal of the purification of a protein from the clear solution produced by centrifugation of a homogenate is to isolate that protein, whose presence and relative molar concentration can be followed by a specific assay, from all of the other proteins present. Improvements in the size, uniformity, and rigidity of the particles of the stationary phase have permitted similar increases in the rate at which chromatography of proteins can be performed. A molecule of protein is a macromolecular poly-electrolyte, the effective charge of which is a function of pH and varies over a wide range. Homogenization of a biological specimen produces a complex mixture of proteins.
