Incomplete inhibition of the immunoglobulin G-binding behavior of nitrated protein A.

Nitration of protein A with tetranitromethane incompletely blocks its Fc-binding ability for immunoglobulin G when measured by more sensitive methods of immunoprecipitation and when tested in the enzyme-linked immunosorbent assay. In addition, binding of protein A and blockage by nitration is heterogeneous and depends on the species origin of the immunoglobulin G.