Dismutase Activity of Copper Complexes

The most efficient catalyst for the dismutation of O, is the [CufHjO) ] complex with a second-order rate constant of 8x 10 s more than twice 

A superoxide dismutase activity has been reported for Cu complexes of amino acids and peptides salicylates penicillamine and indomethacin 

The lower activity of most chelate complexes than that of the aquo complex of Cu was attributed to small amounts of free Cu liberated by the labile complexes The dismutase activity reported for the [Cu(I)gCu(II)g(D-penicillamine)jjCl] complex was suppressed by EDTA or by a Chelex 100 treatment Free Cu cations can, however, not explain the very high second-order rate constant of 6x 10 M s measured at pH 7.0 with the [Cu findomethacin) ] complex by the decay of OJ at 250 nm. With the Cu-histidine complexes, moreover, it was concluded from the influence of pH on the pseudo-first order rate constant of the dismutation of HOj/Oj that [CuHiSjH] was the active species with a second-order rate constant of 3x 10 M s between pH 2 and 7. It was not possible kinetically to distinguish between the classical and the alternative mechanism, with respectively Cu(I) or a Cu(II)—Oj complex as intermediate 

A superoxide dismutase activity had been reported for the Fe-EDTA complex in contrast with the inactivity of the Cu-EDTA complex. It was shown, on the contrary, that Fe-EDTA, instead of catalysing the dismutation of OJ, interferes with the reduction of nitroblue tetrazolium and of Fe(III)-cytochrome c in the assays of the dismutase activity 

Cu chelates of anti-inflammatory and anti-ulcer drugs were often found more active than the free ligands The structure of the Cu(ll) complexes of the anti- 

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