Ion filtration chromatography: A powerful new technique for enzyme purification applied to E. coli alkaline phosphatase

Ion filtration chromatography is a convenient, rapid, and gentle technique for the purification of a single enzyme. It is also readily adapted for large scale preparation. Ion exchange chromatography of an enzyme is accomplished simultaneously with solvent exchange in a single ion filtration step. The enzyme is eluted from the column in a minimal volume and is easily concentrated for storage or additional chromatography. During ion filtration, the enzyme is never exposed to extremes of absorption nor to denaturing solvents. Because ion filtration chromatography is very reproducible, the need for enzyme assays at each step of purification is practically eliminated. This report describes the technology of ion filtration chromatography and explains the unique properties of ion exchange gels which contribute to the ion filtration process. The utility of the technique is illustrated by the purification of E. coli alkaline phosphatase.