Preparation of carrier free [125I]IodoHoechst 33258

Abstract

The DNA ligand Hoechst 33258 has been iodinated with carrier-free [¹²⁵I]iodide by the lactoperoxidase method. The product was separated from other iodination products and the uniodinated compound by preparative thin layer chromatography. ¹²⁵I-labelled Hoechst 33258 is useful as a probe with DNA molecules of defined sequence since the decay of the ¹²⁵I atom results in the induction of a double-strand break, the location of which can be detected by DNA-sequencing techniques.