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Conjugation of DOTA-like chelating agents to peptides and radiolabeling with trivalent metallic isotopes


Peptides can be labeled with various trivalent radiometals for imaging or targeted radionuclide-therapy applications. The peptide is first conjugated to a chelating agent that is able to form stable complexes with the radionuclide of interest. This conjugation step can be carried out as part of the solid-phase peptide synthesis, or it can be undertaken in the solution phase after synthesis and purification of the peptide. The latter route, described here, involves reacting a molar excess of the activated tri-tert-butyl ester-derivatized chelator with a designated free amino group of a peptide analog, in which all other reactive amines are protected, in the presence of a coupling agent. The conjugate molecule is then purified prior to deprotection and further purification by HPLC. The product can be radiolabeled by addition of a suitable metal salt, followed, if necessary, by removal of the unchelated metal. The entire process of conjugation, purification and radiolabeling should take approximately 12.5 h.

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Figure 1: Chemical structures.


  1. Cooper, M.S., Sabbah, E. & Mather, S.J. Conjugation of chelating agents to proteins and radiolabelling with trivalent metallic isotopes. Nat. Protocols, published online 27 June 2006 (doi:10.1038/nprot.2006.49).

  2. Achilefu, S. et al. Novel bioactive and stable neurotensin peptide analogues capable of delivering radiopharmaceuticals and molecular beacons to tumors. J. Med. Chem. 46, 3403–3411 (2003).

    CAS  Article  Google Scholar 

  3. Chan, W.C. & White, P.D. (eds.) Fmoc Solid Phase Peptide Synthesis: A Practical Approach (Oxford University Press, Oxford, UK, 2000).

    Google Scholar 

  4. De Leon-Rodriguez, L.M., Kovacs, Z., Dieckmann, G.R. & Sherry, A.D. Solid-phase synthesis of DOTA-peptides. Chemistry 10, 1149–1155 (2004).

    CAS  Article  Google Scholar 

  5. Reubi, J.C. et al. Unsulfated DTPA- and DOTA-CCK analogs as specific high-affinity ligands for CCK-B receptor-expressing human and rat tissues in vitro and in vivo. Eur. J. Nucl. Med. 25, 481–490 (1998).

    CAS  Article  Google Scholar 

  6. Edreira, M., Melendez-Alafort, L. & Mather, S.J. Optimization of the small-scale synthesis of DOTA-Tyr3-octreotide. Nucl. Med. Commun. 23, 493–499 (2002).

    CAS  Article  Google Scholar 

  7. Heppeler, A. et al. Radiometal-labelled macrocyclic chelator-derivatised somatostatin analogue with superb tumour-targeting properties and potential for receptor-mediated internal radiotherapy. Chem. Eur. J. 5, 1974–1981 (1999).

    CAS  Article  Google Scholar 

  8. Breeman, W.A. et al. Radiolabelling DOTA-peptides with 68Ga. Eur. J. Nucl. Med. Mol. Imaging 32, 478–485 (2005).

    CAS  Article  Google Scholar 

  9. Breeman, W.A., De Jong, M., Visser, T.J., Erion, J.L. & Krenning, E.P. Optimising conditions for radiolabelling of DOTA-peptides with 90Y, 111In and 177Lu at high specific activities. Eur. J. Nucl. Med. Mol. Imaging 30, 917–920 (2003).

    CAS  Article  Google Scholar 

  10. Hainsworth, J.E. & Mather, S.J. Regressive DOTA labelling performance with indium-111 and yttrium-90 over a week of use. Eur. J. Nucl. Med. Mol. Imaging 32, 1348 (2005).

    Article  Google Scholar 

  11. Bio-Rad Laboratories. Chelex 100 and Chelex 20 Chelating Ion Exchange Resin Instruction Manual (Bio-Rad Laboratories, Hercules, CA, 2000).

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Correspondence to Jane K Sosabowski or Stephen J Mather.

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Sosabowski, J., Mather, S. Conjugation of DOTA-like chelating agents to peptides and radiolabeling with trivalent metallic isotopes. Nat Protoc 1, 972–976 (2006).

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