Page 125 - Tyrosine-Based Bioconjugations - Jorick Bruins

Abstract
Proteins can be labelled site-specifically and in inducible fashion by exposing a small peptide tag (G4Y) on any of its termini and activating the newly exposed tyrosine residue with the enzyme mushroom tyrosinase. The enzyme generates a quinone by oxidizing the tyrosine, which in turn can perform strain-promoted oxidation-controlled ortho-quinone cycloaddition (SPOCQ) with strained alkynes and alkenes, generating a stable conjugation product. Here, we describe a protocol to perform SPOCQ reaction on proteins, along with notes to optimize yield and reaction rates. Conjugation efficiencies of over 95% to antibodies have been reported using this protocol.
This work was published as:
Bruins, J. J., van de Wouw, C., Keijzer, J. F., Albada, B., and van Delft, F. L. (2019) Inducible, Selective Labeling of Proteins via Enzymatic Oxidation of Tyrosine, in Enzyme-Mediated Ligation Methods (Nuijens, T., and Schmidt, M., Eds.) pp 357-68, Springer New York, New York, NY.