Antibodies have been utilized for treatment of cancers and other diseases in either its native form (e.g. AstraZeneca’s Fasenra and Imfinzi), or with potent cytotoxic agents conjugated for targeted therapy (e.g. Pfizer’s Ifixi). We have developed a new method of rapid, site-selective and high-yielding conjugation by oxidizing tyrosine residues expressed at the termini of antibodies.
By exposing tyrosine residues via a tetra-glycyltyrosine (G4Y) tag, they become prone to selective enzymatic oxidation by mushroom tyrosinase, which converts the phenol moiety to a quinone. The quinone can perform rapid strain-promoted oxidation-controlled cyclooctyne-1,2-quinone cycloaddition (SPOCQ) with bicyclo[6.1.0]nonyne (BCN),[1a, 2] or cyclopropanated trans-cyclooctene (cpTCO),[1b] resulting in a stable conjugation of a selected probe to an antibody with yields of over 95%.
This method was applied to prepare i.e. antibody-drug conjugates (ADCs) and fluorescently labelled antibodies, and is being used to bi-functionalize antibodies with immunologically relevant proteins such as interleukins, cytotoxic agents and others.
 a) Bruins et. al., Bioconjugate Chem. 2017, 28, 1189-1193; b) Bruins et. al., Chem. Commun., 2018, 54, 7338-7341; c) Bruins et. al., Chem.Eur.J. 2018, 24, 4749 –4756
 a) Borrmann et. al., Bioconjugate Chem. 2015, 26, 257-261; b) Dommerholt et. al., Angew. Chem. Int. Ed. 2010, 49, 9422-9425.
This project was funded by the Institute for Chemical Immunology (ICI)