General method for selective labelling of double-chain cysteine-rich peptides with a lanthanide chelate via solid-phase synthesis

Abstract

The use of lanthanides in preference to radioisotopes as probes for various biological assays has gained enormous popularity. The introduction of lanthanide chelates to peptides/proteins can be carried out either in solution using a commercially available labelling kit or by solid-phase peptide synthesis using an appropriate lanthanide chelate. Herein, a detailed protocol for the latter is provided for the labelling of peptides or small proteins with diethylenetriamine-N, N, N″, N″-tetra-tert-butyl acetate-N'-acetic acid (DTPA) chelate or other similar chelates on a solid support using a chimeric insulin-like peptide composed of human insulin-like peptide 5 (INSL5) A-chain and relaxin-3 B-ch..