Preparation of Disulfide-Bonded Polypeptide Heterodimers by Titration of Thio-Activated Peptides with Thiol-Containing Peptides

Titration of 2-pyridinesulfenyl (SPyr)-protected cysteine-containing peptides with thiol-unprotected peptides has proven to be a superior procedure to selectively generate disulfide-linked peptide heterodimers preventing the formation of homodimers. This procedure was used to synthesize large amounts of highly purified peptide heterodimers consisting of intracellularly active moieties, that were coupled to the third α-helix of the transcription factor Antennapedia, which serves as a ‘shuttle tag’.