Oxygen-evolving complex catalase activity

Another selective inhibitor of the oxygen evolving complex is NH2OH. Treating PS II particles with NH OH (Fig 3) effectively inhibited the oxygen evolution and the water to DCIP reaction. The treatment also resulted in an almost complete (97 %) loss of Mn. The release of Mn correlated well to the inhibition of oxygen evolution and water to DCIP reaction. In contrast, the pseudo catalase activity was only inhibited to some 60 % and was not at all correlated to the release of Mn. Thus, the pseudo catalase activity is not dependent, on either bound or free, Mn. 

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