US Patent 7754861 Method for purifying proteins

The present invention provides methods and kits for purifying a target protein group. The method comprises the steps of contacting a sample comprising at least 95% of the target protein group and at most 5% of contaminating proteins with a library of binding moieties having different binding moieties, binding the contaminating proteins and a minority of the target protein group to the library of binding moieties, separating the unbound target protein group from the proteins bound to the library of binding moieties and collecting the unbound target protein. The collected target protein is more pure than the target protein group in the sample.