[Study of restrictase Sal GI biosynthesis and optimum conditions for its isolation]

The effect of the growing phase of Streptomyces albus G. and the components of the culture medium on the biosynthesis of restriction endonuclease Sal GI was studied. The conditions of DNA sedimentation with streptomycin sulfate and polyethylenimine and separation of proteins with ammonium sulfate were investigated as well. A maximal quantity of the enzyme was observed in the cells in 18-20 h of cultivation in flasks on a shaker. The optimal concentrations of the medium components (g/l) were found by mathematical methods of the experiment planning: glucose--19,0; pepton--5.2; K2HPO4 X 3H2O - 5.0. The optimal concentrations for DNA sedimentation with streptomycin sulfate and polyethylenimine were found to be 1.8-2.0% and 0.2-0.3%, respectively. The optimal concentration of ammonium sulfate for protein separation is 70% of saturation.