title: Radioiodinated bleomycin: stoichiometry of iodination and structural characterization by 1H-nuclear magnetic resonance.
abstract: Bleomycin was iodinated by reaction with iodine monochloride (ICl). A direct relationship was found to exist between the average number of iodine atoms bound per molecule of bleomycin and the ICl: bleomycin molar ratio. Characterization by 1H-NMR analysis denoted that mono, di-, tri- and tetraiodobleomycin are formed when the reacting molar ratios, respectively, are 2:1, 4:1, 6.8:1 and 8.5:1 or greater. The sites of iodination of the bleomycin molecule have been identified to be the imidazole ring which iodinates first, followed by the bithiazole ring system which iodinates last.
mesh_terms: D001761:Bleomycin; D006801:Humans; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods; D009369:Neoplasms / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging
chemical_list: D007457:Iodine Radioisotopes; D001761:Bleomycin