c28h40n2o9

from The Collaborative International Dictionary of English v.0.48

antimycin \an`ti*my"cin\ ([a^]n`t[i^]*m[imac]"s[i^]n), n.
   1. one of several antibiotic substances produced by several
      species of {Streptomyces}, active against various fungi.
      They are used only experimentally, not in medicine. The
      two best-known antimycins are antimycin A1 ({C28H40N2O9})
      and antimycin A3 ({C26H36N2O9}). They are notable for
      their mechanism of action, interference with the proton
      pumping mechanism of fungi.
      [WordNet 1.5 +PJC]