| Abstract: | The antitumor antibiotic, streptonigrin, interacted with zinc, copper, and manganese but not with calcium or magnesium, as indicated by spectral shifts and difference spectra. The titration data showed the formation of 1:1 complexes, and further titration continued to show spectral shifts until a molar ratio for zinc to streptonigrin of 5-10 to 1 was reached. Streptonigrin interacted with DNA only in the presence of a metal ion such as zinc. Streptonigrin titration with DNA at varying zinc molar equivalents revealed that one antibiotic molecule required 5-7 moles of zinc and 20-25 moles of DNA-phosphorus for complexation. Similar values were obtained from gel permeation chromatography. |
