Preferential inhibition of the activity of a stimulatory protein of eukaryotic transcription by platinum (II) complexes.

The effect of platinum(II) complexes on RNA polymerase II was studied. (D-Glucuronato)(1R,2R-cyclohexanediamine)platinum(II) nitrate (II-GHP) preferentially inhibited RNA synthesis in the presence of S-II, an essential component of eukaryotic transcription. When DNA was pretreated with I-GHP, its template activity decreased significantly, especially when assayed in the presence of S-II. The target of platinum(II) complexes is probably DNA. When DNA is modified, regulatory proteins of transcription, such as S-II, seem to lose their function preferentially on such a template, resulting in the inhibition of RNA synthesis.