EFFECT OF NUCLEIC-ACID CONTAMINATION ON PARTITIONING OF PROTEINS IN 2-PHASE PEG-DEXTRAN SYSTEM

Downstream processing of bioproducts results in considerable losses of compounds of interest in a large number of cases. For the intracellul ar enzyme tartrate dehydrogenase, an analysis of the laboratory proces s for enzyme recovery revealed that maximum losses occur in the initia l stages of purification when the enzyme is separated from nucleic aci ds and other undesirable enzymes. Hence, aqueous two-phase extraction was studied to investigate the separation of several enzymes from nucl eic acids. Single-component and binary equilibria for three commercial ly available enzymes (bovine serum albumin, trypsin, chymotrypsin) and yeast RNA were studied in a two-phase system consisting of dextran an d polyethylene glycol (PEG). The effects of pH and concentrations of t he components and salts (NaCl) were investigated.