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Updated: Jul 11, 2026

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry
Published on: July 20, 2016
Catalysis of imido group hydrolysis in a maleimide conjugate
1Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA.
Abstract:
Maleimides are often used for biomolecular conjugation with thiols. An underappreciated aspect of the imido group in a maleimide conjugate is its susceptibility to spontaneous hydrolysis, resulting in undesirable heterogeneity. Here, a chromophoric maleimide is used to demonstrate that both molybdate and chromate catalyze the hydrolysis of an imido group near neutral pH. Tungstate and 4-(dimethylamino)pyridine are less effective as catalysts. This work reveals a new mode of chemical reactivity for molybdate and chromate, and provides a strategy for decreasing the heterogeneity of bioconjugates derived from maleimides.
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