Related Experiment Video
Updated: Jul 27, 2026

Chemoselective Modification of Viral Surfaces via Bioorthogonal Click Chemistry
Published on: August 19, 2012
Fast and selective labeling of N-terminal cysteines at neutral pH via thiazolidino boronate formation
Anupam Bandyopadhyay1, Samantha Cambray1, Jianmin Gao1
1A Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon Street, Chestnut Hill, MA 02467.
Abstract:
Facile labeling of proteins of interest is highly desirable in proteomic research as well as in the development of protein therapeutics. Herein we report a novel method that allows for fast and selective labeling of proteins with an N-terminal cysteine. Although N-terminal cysteines are well known to conjugate with aldehydes to give thiazolidines, the reaction requires acidic conditions and suffers from slow kinetics. We show that benzaldehyde with an ortho-boronic acid substituent readily reacts with N-terminal cysteines at neutral pH, giving rate constants on the order of 103 M-1 s-1. The product features a thiazolidono boronate (TzB) structure and exhibits improved stability due to formation of the B-N dative bond. While stable at neutral pH, the TzB complex dissociates upon mild acidification. These characteristics make the TzB conjugation chemistry potentially useful for the development of drug-protein conjugates that release the small molecule drug in acidic endosomes.
More Related Videos
10:36Covalent Labeling with Diethylpyrocarbonate for Studying Protein Higher-Order Structure by Mass Spectrometry
Published on: June 15, 2021
07:16Resin-Assisted Capture Coupled with Isobaric Tandem Mass Tag Labeling for Multiplexed Quantification of Protein Thiol Oxidation
Published on: June 21, 2021
Related Concept Videos
Preparation and Reactions of Thiols
Preparation of Nitriles
Electrophilic Aromatic Substitution: Nitration of Benzene
Nucleophilic Aromatic Substitution: Elimination–Addition
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene