Steffimycin B is an anthracycline metabolite isolated from a Streptomyces sp. with antibacterial and antineoplastic properties. Crystallographic studies of binding to DNA suggest that it has a higher CpG base sequence specificity over the TpA step, similar to that of daunorubicin and nogalamycin. A close analog was shown to be active against ras oncogene-expressed cells.
Steffimycin B is soluble in ethanol, methanol, DMF and DMSO.