Abstract: Soluble azoles in aqueous solutions can be used as virucidal agents for biologically active protein preparations.

Abstract: Soluble, intermediate length alcohols (C.sub.4 -C.sub.10) in aqueous solutions at low pH (4.0-7.0) can be used as virucidal agents for therapeutic biologically active protein preparations. Treatment with the alcohols is especially useful for proteins having activity not adversely affected by low pH.

Abstract: Controlled enzymatic treatment may be used to selectively degrade undesirable contaminants to a size or charge range which can be more readily removed by subsequent separation steps. Treatment is especially useful for purifying rDNA or monoclonal antibody culture products by using nuclease enzyme treatment to degrade undesirable residual nucleic acids to a molecular size or charge range sufficiently different from the product to be purified so that this difference can be exploited in a subsequent purification step (e.g. precipitation, size exclusion chromatography or ion exchange chromatography). The nuclease enzyme treatment is done in the presence of a detergent.

Abstract: There is disclosed an improved method for separating and recovering proteins, particularly therapeutically active proteins, from an aqueous system also containing a component having the ability to create two liquid phases by use of salt partitioning technology. By the addition of water soluble inorganic salts to an aqueous system containing one or more therapeutically active proteins or nucleic acids, especially an aqueous system obtained from fractionation of a blood plasma fraction or from a tissue culture fluid resulting from a biotechnology production operation such as recombinant DNA and monoclonal antibody technologies, the aqueous system may be separated into two or more liquid phases. Such separated phases may be selectively enriched in components of the original aqueous system having differing solubility in the so-separated liquid phases.