DETOXIFICATION OF HYDROGEN-PEROXIDE BY THE RABBIT IRIS-CILIARY BODY

When the intact rabbit iris-ciliary body was incubated in Tyrode''s solution containing 10-4 M hydrogen peroxide, the concentration of hydrogen peroxide remaining in solution diminished rapidly. The iris-ciliary body was homogenized and centrifuged at 100,000 g. The hydrogen peroxide detoxification activity was resident primarily in the 100,000 g supernatant and not in the pellet. The hydrogen peroxide detoxification activity was found to be inactivated by heat and to be nondialyzable. Gel filtration chromatography experiments revealed that breakdown of hydrogen peroxide by the ciliary body was not a ''bulk effect'' due to generalized oxidation of tissue constituents. In fact, the active principle, localized by gel filtration chromatography, identified closely with catalase. Apparently, catalase within the iris-ciliary body enables the tissue to detoxify hydrogen peroxide from solution. Catalase might protect the iris-ciliary body from damage by hydrogen peroxide generated by normal physiological or pathophysiological conditions.