Orientational, conformational stability and surface potential of immunoglobulins in monomolecular layers

Orientation, resistance to surface denaturation and surface potential of bovine and horse immunoglobulin G (IgG) and also of pig IgG-antibodies against DNP and DNS groups on the surface of NaCl solutions of various concentrations have been studied by monomolecular layer method. High conformational stability of IgG molecules of all the species was confirmed. At the surface of NaCl solutions with concentrations 0.15--0.5 M immunoglobulins of all species from monolayers consisting of practically non-unfolded molecules with such an orientation, that all the fragments of IgG molecule are located horizontally. Beyond the limits of this native structure stability zone the rate of surface denaturation is directly proportional to NaCl concentration in the solution. The values of surface potentials of all immunoglobulins under study are close to each other and change little with the surface denaturation.