Antibodies to a Distinct Antigenic Determinant of Staphylococcal Nuclease

Abstract Antibodies to staphylococcal nuclease have been fractionated on immunoabsorbent columns bearing selected polypeptide fragments of the enzyme. By this means a population of antibodies specific for a distinct antigenic determinant in the helix-rich, carboxyl-terminal third of nuclease was prepared. The monospecificity of these antibodies was operationally defined by ultracentrifugal analysis in the presence of nuclease. Although prepared against the intact, native nuclease molecule these antibodies are able to bind to a disordered polypeptide fragment thereof. It is postulated that the native antigenic determinant may be generated in such a fragment by spontaneous folding of the polypeptide chain.