Article thumbnail
Location of Repository

How do HYNIC-conjugated peptides bind technetium? Insights from LC-MS and stability studies

By Robert C. King, M. Bashir-Uddin Surfraz, Stefano C. G. Biagini, Philip J. Blower and Stephen J. Mather

Abstract

Hydrazinonicotinamide (HYNIC) is an established bifunctional complexing agent for technetium-99m ((99m)Tc) but the structure of the technetium coordination sphere remains uncertain. To gain further insight into this, we have prepared conjugates of HYNIC and hydrazinobenzoic acid (HYBA) with a model peptide, and radiolabelled them with (99m)Tc using three well-established co-ligand systems: EDDA, tricine and tricine-nicotinic acid. The labelled peptides were studied by LC-MS and by subjecting them to serum stability and protein binding assays. For each co-ligand system, HYNIC conjugates formed fewer and more stable labelled species than the corresponding HYBA conjugates. LC-MS analysis showed that all conjugates contained one hydrazine moiety bound to Tc, that binding of Tc to HYNIC-peptide and co-ligand occurs with displacement of 5H(+) indicating a Tc formal oxidation state of +5, and that the Tc has no oxo- or halide ligands. LC-MS also shows that complexes formed with the HYNIC conjugate contain fewer coordinating co-ligand molecules than the HYBA conjugate indicating that HYNIC is able to more effectively satisfy the coordination requirement of technetium, perhaps by binding in chelating mode

Topics: Q, QD
Publisher: Royal Society of Chemistry
Year: 2007
DOI identifier: 10.1039/b705111e
OAI identifier: oai:kar.kent.ac.uk:8030
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • http://dx.doi.org/10.1039/b705... (external link)
  • Suggested articles


    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.