PURIFICATION OF A STREPTOCOCCAL DEOXYRIBONUCLEASE BY AFFINITY-CHROMATOGRAPHY BASED ON A DNA-CELLULOSE MATRIX

An affinity chromatography method, using double stranded DNA, is descr ibed for the isolation of a deoxyribonuclease from the medicament Vari dase, a wound cleansing preparation produced from the extracellular pr oducts of a species of Streptococcus. Using a complex buffer system, w hich includes EDTA, mercaptoethanol, bovine serum albumin and 50 mM Na Cl, conditions are produced which allow binding of the nuclease to the chromatographic matrix without apparent degradation of the DNA. Incre asing the NaCl concentration to 2 M results in the elution and isolati on of a relatively non-specific endonuclease with a molecular mass of approximately 38 000 and a pi of 4.6. Experiments using ammonium sulph ate for partial fractionation of the Varidase proteins, prior to chrom atography, improved the yield but were not essential for obtaining a p urified product. It is suggested that this technique should be readily applicable for the isolation of deoxyribonucleases from other sources . (C) 1997 Elsevier Science B.V.