Superoxide ion distribution

HP here is great interest in the biochemistry and relevant coordination chemistry of copper-containing proteins (1,2, 3, 4, 5). They are widely distributed in both plants and animals and are often involved in oxygen metabolism, transport, and use. One of the most actively studied copper proteins is bovine erythrocyte superoxide dismutase (SOD) (6,7,8). This enzyme catalyzes the dismutation of superoxide ion, Reaction 1. 

These ions were first prepared by Werner who formulated them as peroxo-bridged complexes of Co111 and Colv. Esr data have shown, however, that the single unpaired electron is distributed equally over both cobalt ions, thus ruling out that description. The problem of how best to formulate these complexes has been fairly conclusively settled by X-ray structural data5 which are summarized in Fig. 25-F-2. The O—O distances are not significantly different from that (1.28 A) characteristic of superoxide ion, 02. 

By employing anionic techniques, alkyl methacrylate containing block copolymer systems have been synthesized with controlled compositions, predictable molecular weights and narrow molecular weight distributions. Subsequent hydrolysis of the ester functionality to the metal carboxylate or carboxylic acid can be achieved either by potassium superoxide or the acid catalyzed hydrolysis of t-butyl methacrylate blocks. The presence of acid and ion groups has a profound effect on the solution and bulk mechanical behavior of the derived systems. The synthesis and characterization of various substituted styrene and all-acrylic block copolymer precursors with alkyl methacrylates will be discussed. 

Both the inhibition of this effect by CN ions, which form complexes with the enzyme metal cations, and the change in the distribution of the degradation intermediates at equivalent transformation rates of the organic pollutant, with or without an enzyme, suggest that the observed phenomenon really stemmed from the catalytic activity of SOD. These results emphasize the importance of superoxide. 

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