The removal of nucleic acids from microbial extracts by precipitation with lysozyme

Abstract

It is usually necessary to remove nucleic acids from microbial extracts in order to avoid their interference with the isolation of enzymes from the extract. This may be particularly important where the purification procedure includes chromatography on an anion-exchange column such as DEAE-Sephadex (1). Methods that have been used have included precipitation with Mn, destruction of the nucleic acids with nucleases, and precipitation with basic substances, usually protamine sulfate or streptomycin sulfate. It is likely that there may be advantages, in some cases at least, in using other basic proteins for this purpose, since the results obtained with the previous methods have not always been satisfactory. The procedure described in this paper utilizes high concentrations of lysozyme to precipitate nucleic acids from a bacterial extract. The separation obtained with lysozyme was efficient, reproducible, and superior to the separation obtained with protamine sulfate.