Abstract
A precursor system for formation of streptomycin was investigated with a cell-free supernatant obtained from suspension of young mycelium of Streptomyces griseus in a non-growth medium containing only glucose and sodium chloride. When the supernatant was kept at a slightly alkaline condition for a day, a remarkable development of antibiotic potency was observed, while the supernatant itself had a very weak potency. It was made clear by column chromatography with Sephadex G-25, CM-cellulose and DEAE-cellulose that materials required for incearse of antibiotic potency in the supernatant consisted of a cationic component with low molecular weight and an anionic one with high molecular weight. Although each of the components showed little change in antibiotic potency, the mixture of them gave rise to a remarkable increase in antibiotic potency at a slightly alkaline condition. Thus, these two components were considered to construct the precursor system appearing in the supernatant and to be able to react in a cell-free state creating the antibiotic potency.
The optimum pH for the reaction occuring in the supernatant was about 9. This reaction was inhibited by phosphate or ethylenediaminetetraacetate, but not by arsenate. The precursor system was stable at and below 50°C.
