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Updated: Apr 12, 2026

Antibody Labeling with Fluorescent Dyes Using Magnetic Protein A and Protein G Beads
Published on: September 15, 2016
Cleavable ester-linked magnetic nanoparticles for labeling of solvent-exposed primary amine groups of
Ujwal S Patil1, Laura Osorno1, Angela Ellender1
1Department of Chemistry, University of New Orleans, New Orleans, LA 70148, USA.
Abstract:
To study the solvent-exposed lysine residues of peptides/proteins, we previously reported disulfide-linked N-hydroxysuccinimide ester-modified silica-coated iron oxide magnetic nanoparticles (NHS-SS-SiO2@Fe3O4 MNPs). The presence of a disulfide bond in the linker limits the use of disulfide reducing agent during protein digestion and allows unwanted disulfide formation between the MNPs and protein. In the current work, the disulfide bond was replaced with a cleavable ester group to synthesize NHS ester-modified SiO2@Fe3O4 MNPs. Use of the cleavable ester group provides an improved method for protein labeling and allows the use of disulfide reducing agents during protein digestion.
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