Figure 6.

Collections of bioorthogonal chemistries for multicomponent labeling. (A) Three mechanistically distinct reactions – [4+1] tetrazine (Tz₁)-isonitrile cycloaddition, [4+2] tetrazine (Tz₂)-TCO cycloaddition, and [3+2] azide-alkyne cycloaddition – were used to simultaneously label three model proteins (BSA, OVA, and lysozyme). (B) Covalent protein adducts were visualized via gel electrophoresis followed by fluorescence scanning. No cross-reactivities were detected. Part B was adapted with permission from ref.²²³, Wiley-VCH.