A new human catalytic antibody Se‐scFv‐2D8 and its selenium‐containing single domains with high GPX activity

Glutathione peroxidase (GPX) is a well‐known antioxidant selenoenzyme, which can catalyze the reduction of a variety of hydroperoxides and consequently protect cells and other biological tissues against oxidative damage. Many attempts have been made to mimic its function, and a human catalytic antibody Se‐scFv‐B3 with GPX activity has been prepared in our previous study. This time, a new clone 2D8 that bound specifically to the glutathione analog GSH‐S‐DNPBu was selected again by using the technology of phage display antibody library, and then scFv‐2D8 was successfully expressed in soluble form and purified using Ni²⁺‐immobilized metal affinity chromatography. After being converted into selenium‐containing scFv by chemically modification, it showed higher GPX activity than previous abzyme Se‐scFv‐B3. The heavy chain variable fragment of scFv‐2D8 was also prepared and converted into selenium‐containing protein using the same method. This selenium‐containing single‐domain antibody showed some GPX activity and, to the best of our knowledge, is the first human single‐domain abzyme with GPX activity, which lays a foundation for preparing GPX abzyme with human origin, lower molecular weight and higher activity. Copyright © 2009 John Wiley & Sons, Ltd.