Lanthanide-based time-resolved fluorescence of in cyto ligand-receptor interactions

Anal Biochem. 2004 Jul 15;330(2):242-50. doi: 10.1016/j.ab.2004.04.012.


A lanthanide-based assay for ligand-receptor interactions provides an attractive alternative to the traditional radiolabeled determinations in terms of sensitivity, throughput, and biohazards. We designed and tested peptide ligands modified with an Eu-DTPA chelate. These labeled ligands were used in competitive binding assays with results comparable to those obtained using the traditional radiolabeled binding assays. The sensitivity of time-resolved fluorescence is sufficient to detect attomoles of europium, allowing assays in 96-well plates, compared with 30-mm dishes for (125)I binding assays to whole cells. We verified binding of Eu-DTPA-NDP-alpha-MSH to cells overexpressing the human melanocortin-4 receptor. The Eu-labeled ligand bound to these cells with an affinity similar to that of unlabeled NDP-alpha-MSH and was used to optimize a competitive binding assay. The lanthanide-based assays provided superior results with higher throughput and eliminated the need for radioactive waste disposal. This assay is appropriate for high-throughput screening of ligand libraries.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Validation Study

MeSH terms

  • Binding, Competitive
  • Cytological Techniques
  • Fluorescence
  • Humans
  • Lanthanoid Series Elements / chemistry*
  • Ligands
  • Peptides / metabolism
  • Protein Array Analysis / methods*
  • Receptor, Melanocortin, Type 4 / metabolism
  • Receptors, Cell Surface / metabolism*
  • Time


  • Lanthanoid Series Elements
  • Ligands
  • Peptides
  • Receptor, Melanocortin, Type 4
  • Receptors, Cell Surface