Determination of protein in polysaccharide-antibody complexes

We describe a simple and sensitive method for determining antibody protein complexed with polysaccharide using binding of Amido-black to antigen-antibody complexes and bovine serum albumin as protein standard. The method, which is a modification of the method used for the determination of total nitrogen or the protein concentration in milk, has shown a consistent quantitative relationship with the Lowry procedure and has been developed for its particular application to serological precipitates.