Rapid, Stable, Chemoselective Labeling of Thiols with Julia–Kocieński‐like Reagents: A Serum‐Stable Alternative to Maleimide‐Based Protein Conjugation

Abstract

Exquisite chemoselectivity for cysteine has been found for methylsulfonylphenyloxadiazole compounds under various buffer conditions. Furthermore, the resulting protein conjugates have superior stability to cysteine–maleimide conjugates in human plasma (HSA=human serum albumin, MBP-C-HA=maltose-binding protein). This new thiol-click reaction offers a new approach to generate stable protein conjugates and Pegylated proteins.