| abstract |
The invention relates to a method of preparing a protein or a proteinaceous material labelled with a metal-radionuclide and intended for diagnostic or therapeutic application, by reacting a protein or a proteinaceous material with an agent for coupling the radionuclide to the protein or the proteinaceous material, a protein conjugate being formed, and by then complexing the radionuclide with the conjugate thus formed to a radionuclide complex. A coupling agent is used which consists at least substantially of a thio compound of the general formula Y-R-S-X, wherein X is a hydrogen atom or a suitable protective group, R is a branched or non-branched, optionally substituted hydrocarbon radical having 1-10 carbon atoms, which may be interrupted by one or more hetero atoms, and Y is at least one terminal reactive group capable of reacting with a functional group from the protein or the proteinaceous material; or a cyclic condensation product of the thio compound of formula (I) having 5-7 ring atoms, wherein X and Y together constitute a reactive group capable of reacting with a functional group from the protein or the proteinaceous material; or a water-soluble salt of this condensation product. The invention also relates to novel compounds useful as coupling agents and protein conjugates made from them. The invention further relates to the labelled protein or proteinaceous material thus obtained and to a kit for the preparation of a radiopharmaceutical composition which comprises a protein conjuguate formed by reaction of a protern or a proteinaceous material with the coupling agent mentioned hereinbefore. |