Use of Streptomycin in the Separation of Nucleic Acids from Protein in a Bacterial Extract

Abstract

IT is well known that in bacterial extracts, in contrast to extracts from animal tissues, nucleic acids interfere markedly with the isolation and separation of proteins, for example in chromatographic separation on substituted cellulose columns. Protamine sulphate and manganese chloride¹ have been used to precipitate selectively nucleic acids from the protein; these methods have often proved difficult and have resulted in much loss of protein. More recently, streptomycin or dihydrostreptomycin² have been used. In order satisfactorily to separate the protein components of an extract of Lactobacillus plantarum (N.C.I.B. 6376) it was necessary to reduce the nucleic acid content of these extracts. The protamine sulphate method was found to be unreliable due to lack of reproducibility, even under rigidly controlled conditions. Accordingly, the streptomycin method was investigated.