Superoxide production contributes to osteoclastic bone resorption. Evidence strongly
indicates that NADPH oxidase is an enzyme system responsible for superoxide generation
in osteoclasts. A membrane-bound subunit, p91, is the catalytic domain of NADPH oxidase.
However, osteoclasts from p91 knockout mice still produce superoxide at a rate similar to
that observed in wild type mice. This unexpected phenomenon prompted us to examine the
osteoclasts for an alternative to the p91-containing oxidase. In this study, the cloning of a …