Using triazine-thiol exchange, a group from Nijmegen was able to program cysteine modifications in peptides by varying the pH, they report in ChemistryEurope.

Modifying peptides or proteins for therapeutic applications presents the challenge of selectivity. ‘These biomolecules have many different functional groups, so it’s not straightforward to selectively modify one of them’, says Kevin Neumann, assistant professor at Radboud University (RU). ‘In addition to selecting the targeted functionality, controlling the site of modification would be highly advantageous. Ultimately, we want to attach cytotoxic drug molecules to something, so ideally we want to know exactly which sites are covered and how many of them there are.’