Disuccinimidyl glutarate (DSG) is a homobifunctional crosslinker that contains two N-hydroxysuccinimide (NHS) ester groups at each end of a short 5-atom (7.7 angstrom) spacer.
DSG is a membrane-permeable and non-cleavable crosslinker, allowing for intracellular labeling of peptides and proteins. NHS esters react with amines of lysine residues and N-termini of peptides and proteins, forming a covalent amide bond and releasing the NHS group. DSG is commonly used to pair radiolabelled ligands to cell surface receptors and determine DNA-protein binding interactions in ChIP assays. DSG labeling is often combined with formaldehyde fixation to improve the detection of DNA-protein complexes.
DSG is water-insoluble and must be dissolved in an organic solvent, such as DMSO or DMF, before being added to aqueous solutions.
