17α-ethynylestradiol peptide labeling by 'click' chemistry

A synthesis of 17α-ethynylestradiol-labeled native peptides is reported. The peptide moiety is tethered to the steroid hormone by a 1,2,3-triazole bridge formed by a CuAAC reaction in which the azido group of the peptide combines with the terminal acetylenic moiety of ethynylestradiol to link the two bioactive molecules. Thus bioconjugates containing the hormone moiety at three positions within the peptide molecule could be useful targets for hormono-enzyme interaction studies.