APPLICATION OF VESICLE CHROMATOGRAPHY IN PROTEIN-PURIFICATION

A recently described vesicular packing material (VP) representing clusters of microcapsules (derived from plant cells) was tested with respect to its application for protein purification. Protein elution behaviour was investigated with 28 defined proteins and several protein containing preparations and biological fluids. All proteins were eluted with a neutral buffer without retardation as peaks in the permeable or excluded fraction. Due to its sharp separation limits VP can be used for the separation of proteins with small differences in size. In special cases, proteins of nearly equal molecular weight (e.g. carboxypeptidase A and pepsin) may be separated due to differences in the electrical charge of the protein molecules and resulting differences in the electric interaction with the negatively charged polygalacturonan matrix of the vesicle membrane (cell wall). Vesicle chromatography is a biocompatible process. The VP may be applied on a large scale. Complete separation between excluded and permeable proteins may be reached if the columns are loaded with concentrated protein samples (e.g., blood plasma). Size fractionation by the VP seems to be applicable in the following fields: 1. Preparative separation of an excluded protein from an excess of permeable macromolecules, especially if the difference in STOKES' diameter is too small for an effective separation by gel chromatography or conventional membrane techniques. 2. Preparative separation of permeable proteins from an excess of excluded proteins. 3. Chromatography of proteins in the presence of alcohol, polyethylene glycol or detergents.