Biotin–Protein Ratios and Stability of Biotinylated Immunoglobulins as Standards for the Quantitation of Biotin-Binding Immunoglobulins

Abstract

Biotin-binding IgG in human sera was quantitated using F(ab')₂anti-human IgG-coated multiwell microplates (Muratsugu, M. et al. 2003, Biol. Pharm. Bull., 26, 1605—1608). The biotin–protein ratio of biotinylated IgG, which was used as standard in the assay, was very important to quantitate the level of biotin-binding IgG. We investigated a synthesis method of biotinylated human immunoglobulins, how to determine the biotin–protein ratio of the biotinylated proteins, and their stability to prepare standards for measuring biotin-binding IgG, IgA, and IgM.