Development of Lanthanide-Labeled Human INSL3 as an Alternative Probe to Radioactively Labeled INSL3 for Use in Bioassays


Address for correspondence: Professor John D. Wade, CChem CSci FRACI FRSC, Howard Florey Institute, University of Melbourne, Victoria 3010, Australia. Voice: +61 3 8344 7285; fax: +61 3 9348 1707.


The use of radioisotope-labeled peptides and proteins in bioassays is diminishing as a consequence of the emergence of fluorescent lanthanide-labeled probes. We describe a simple, single-step labeling of synthetic human insulin-like peptide 3 (INSL3) with a commercially available activated europium chelator. The labeled peptide was then used for the development of a robust and highly reproducible receptor-binding assay which is amenable to automated high-throughput screening of ligands. Europium-labeled INSL3 showed a similar binding profile to radioactively labeled INSL3.