Sulfo S-4FB Linker (Water Soluble), 5 x 1 mg. S-4FB heterobifunctional crosslinker is fundamental to SoluLINK bioconjugation technology. Sulfo-S-4FB reacts with primary amines on proteins (through lysine amino acids) or amino-modified oligonucleotides or surfaces, introducing a 4FB linker that forms stable covalent conjugates with biomolecules possessing HyNic linkers. Sulfo-S-4FB contains a Sulfo-NHS ester, which makes this linker water soluble. No DMF or other organic solvents are necessary to dissolve the linker prior to use.