G-Biosciences offers two different HOOK™ IgG Biotinylation Kits for labeling antibodies, either through free amines or sulfhydryls.

G-Biosciences' HOOK™ IgG Biotinylation (Amine) kit is designed for the efficient biotinylation of IgG molecules by immobilizing the IgG molecules on a solid support. IgG molecules contain a histidine-rich region in their Fc region. This feature is used to first immobilize the IgG molecules on a nickel chelating resin support. The immobilized IgG molecule is then incubated with NHS-dPEG₄-Biotin solution to biotinylated the free amine groups. The free NHS-dPEG₄-Biotin is washed away and the biotinylated IgG is eluted with an imidazole containing buffer. The biotinylation of the IgG on the Nickel Chelating resin results in the addition of three to five biotin molecules per IgG molecule.

G-Biosciences' HOOK™ IgG Biotinylation (Sulfhydryl) kit is designed for the efficient biotinylation of IgG molecules by immobilizing the IgG molecules on a solid support.IgG molecules contain a histidine rich region in their Fc region and this feature is used to first immobilize the IgG molecules on a nickel chelating resin support. The disulfide bonds of the immobilized IgG molecule are then reduced with the supplied Protein-S-S-Reductant™, with excess reductant being simply washed away. The reduced immobilized IgG molecule is then incubated with PEG₂-Iodoacetyl-Biotin solution to biotinylated the free sulfhydryl groups. The free PEG₂-Iodoacetyl-Biotin is washed away and the biotinylated IgG is eluted with an imidazole containing buffer. The biotinylation of the IgG on the Nickel Chelating resin results in the addition of two to four biotin molecules per IgG molecule.

For both kits, the rapid removal of uncoupled biotin eliminates the need for further dialysis or desalting of the biotinylated antibody. The long hydrophilic spacer arm conveys its water solubility to the molecule that it is coupled to. This means that antibodies and other proteins labeled with G-Biosciences' NHS-dPEG₄-Biotin (amine) or PEG₂-Iodoacetyl-Biotin (sulfhydryl) have a reduced occurrence of aggregation compared to non-PEG biotinylation reactions.

The kits are supplied with a Nickel Chelating column that can be used up to ten times, and G-Biosciences' single-use aliquots of NHS-dPEG₄-Biotin (with the amine biotinylation kit) and PEG₂-Iodoacetyl-Biotin (with the sulfhydryl biotinylation kit). Each kit is suitable for the coupling of one to ten milligrams of protein in one milliliter buffer, suitable for 8 couplings.