Biotin Labeling Kit-SH is mainly used for the preparation of biotin-labeled IgG for enzyme immunoassay (EIA).The kit contains all the reagents necessary for the labeling. The reducing agent included in this kit creates sulfhydryl groups in the IgG molecule. Because the reducing agent is a water-soluble phosphine compound, it can be removed by a filtration tube with a simple process. An average of 5 to 8 biotin molecules conjugate to each IgG molecule.