An Fv catalytic antibody with high glutathione peroxidase activity

An Fv catalytic antibody with high glutathione peroxidase (GPX) activity was prepared using proteolysis of a monoclonal antibody 3H4 (IgM), and subsequent chemical mutation. The Fv fragment generated by pepsin digestion of 3H4 retained binding activity for glutathione (GSH), one substrate of GPX. Active serines in the binding site of the Fv fragment were converted to selenocysteine, the catalytic group of GPX. The selenium-containing Fv fragment exhibits a high GPX activity of the same order of magnitude as native GPX from rabbit liver.