Comparative studies in molecular stability of immunoglobulin G from different species.

1. Molecular stability of immunoglobulin G (IgG) from chicken and four mammalian species (cow, goat, pig and rabbit) was compared from immunochemical and biochemical view-points. 2. IgG from cow, goat and pig showed similar stability against denaturation caused by heat, acid and denaturant treatments, while rabbit IgG was shown to be more resistant to all of the treatments than other mammalian IgGs, suggesting that rabbit IgG has a highly stable molecular structure. 3. The heat- and acid-stability of chicken IgG measured by immunochemical methods were similar to those of cow, goat and pig IgG. Conformational stability of chicken IgG measured by fluorometric and enzymatic methods, however, was lower than the mammalian IgGs, suggesting that chicken IgG has a more flexible and unstable molecular structure.