Issue 25, 2020

Cysteine specific bioconjugation with benzyl isothiocyanates


Protein labelling has a wide variety of applications in medicinal chemistry and chemical biology. In addition to covalent inhibition, specific labelling of biomolecules with fluorescent dyes is important in both target discovery, validation and diagnostics. Our research was conducted through the fragment-based development of a new benzyl-isothiocyanate-activated fluorescent dye based on the fluorescein scaffold. This molecule was evaluated against fluorescein isothiocyanate, a prevalent labelling agent. The reactivity and selectivity of phenyl- and benzyl isothiocyanate were compared at different pHs, and their activity was tested on several protein targets. Finally, the clinically approved antibody trastuzumab (and it's Fab fragment) were specifically labelled through reaction with free cysteines reductively liberated from their interchain disulfide bonds. The newly developed benzyl-fluorescein isothiocyanate and its optimized labelling protocol stands to be a valuable addition to the tool kit of chemical biology.

Graphical abstract: Cysteine specific bioconjugation with benzyl isothiocyanates

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Article information

Article type
25 Nov 2019
02 Apr 2020
First published
16 Apr 2020
This article is Open Access
Creative Commons BY license

RSC Adv., 2020,10, 14928-14936

Cysteine specific bioconjugation with benzyl isothiocyanates

L. Petri, P. A. Szijj, Á. Kelemen, T. Imre, Á. Gömöry, M. T. W. Lee, K. Hegedűs, P. Ábrányi-Balogh, V. Chudasama and G. M. Keserű, RSC Adv., 2020, 10, 14928 DOI: 10.1039/D0RA02934C

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