Polyclonal-antibody-mediated insolubilization and stabilization of papain

Antisera raised in rabbits against native iodoacetamide- and iodoacetic acid-modified papain contained precipitating and non-inhibitory antibodies. Papain could be insolubilized as enzyme–antibody adducts with the -globulin fraction derived from the antiserum. Two insolubilized papain preparations, designated A and B, with low and high antibody/enzyme ratios, respectively, exhibited high enzyme activity and markedly enhanced thermal and denaturant stabilities. However, papain antibody adduct B was superior in activity and stability over preparation A. The usefulness of immobilized papain in biopharmaceutical and other industries is also discussed.