Evaluation of bicinchoninic acid as a ligand for copper(I)-catalyzed azide-alkyne bioconjugations

Erik H Christen, Raphael J Gübeli, Beate Kaufmann, Lars Merkel, Ronald Schoenmakers, Nediljko Budisa, Martin Fussenegger, Wilfried Weber*, Birgit Wiltschi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The Cu(I)-catalyzed cycloaddition of terminal azides and alkynes (click chemistry) represents a highly specific reaction for the functionalization of biomolecules with chemical moieties such as dyes or polymer matrices. In this study we evaluate the use of bicinchoninic acid (BCA) as a ligand for Cu(I) under physiological reaction conditions. We demonstrate that the BCA-Cu(I)-complex represents an efficient catalyst for the conjugation of fluorophores or biotin to alkyne- or azide-functionalized proteins resulting in increased or at least equal reaction yields compared to commonly used catalysts like Cu(I) in complex with TBTA (tris[(1-benzyl-1H-1,2,3-triazol-4-yl)methyl]amine) or BPAA (bathophenanthroline disulfonic acid). The stabilization of Cu(I) with BCA represents a new strategy for achieving highly efficient bioconjugation reactions under physiological conditions in many application fields.

Original languageEnglish
Pages (from-to)6629-32
Number of pages4
JournalOrganic and Biomolecular Chemistry
Issue number33
Publication statusPublished - 7 Sept 2012


  • Alkynes/chemistry
  • Azides/chemistry
  • Catalysis
  • Click Chemistry/methods
  • Coloring Agents/chemistry
  • Coordination Complexes/chemistry
  • Copper/chemistry
  • Cycloaddition Reaction/methods
  • Ligands
  • Lipase/chemistry
  • Quinolines/chemistry
  • Thermoanaerobacter/enzymology

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