Hydroperoxide lysis

The lack of inhibition of lysis by catalase in the resealed vesicles prompted the proposal that the precursor which reacted with O to form the lytic species was not H2O2 but instead a lipid hydroperoxide the marked sensitization of the vesicles to the lytic effects of O , which prior photooxidation produced, was consistent with this proposal. Lysis of bovine red cells exposed to Oj , however, was inhibited by superoxide dismutase but not by catalase. ... 

Therefore, the radical coupling occurs easily to give a hydroperoxyben-zoquinone intermediate, which is converted to benzoquinone, completing the catalytic cycle. When the phenol is hindered, the inner-sphere coupling between the phenoxide and hydroperoxide does not proceed effectively and homo lysis of the Cu(II)—OPh bond occurs. The resultant phenoxy radicals couple together to give the diphenoquinone. 

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