Two epitopes responsible for the catalytic activity of heme oxygenase‐1 identified by phage display

Heme oxygenase‐1 (HO‐1) catalyzes the oxidative degradation of heme. The catalytic mechanism of the HO‐1 reaction has been determined gradually by studies of its crystal structure and HO‐1 mutants. However, the neutralizing epitopes responsible for HO‐1 activity remain elusive. Screening of a phage display library revealed four epitopes that could interact with the polyclonal antibody prepared by immunizing rabbits with the purified HO‐1 protein. Two of these four epitopes are responsible for HO‐1 catalytic activity because their antibodies were able to neutralize HO‐1 activity. The results of the present study shed further light on the molecular character of HO‐1.