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Publisher Summary The key biological function of copper is undoubtedly its involvement in the cytochrome c oxidase of the mitochondrial respiratory chain. Copper is now known to be an essential component in several oxidases that play important roles in more peripheral parts of the metabolism of microorganisms, plants, and animals. This chapter describes an extensive section on superoxide dismutase. As the dismutase is not an oxidase, it may appear that the only logic behind this is that the protein contains copper. Superoxide is the primary reduction product of dioxygen with some oxidases—for example, xanthine oxidase, and its formation in some reactions involving copper-containing oxidases yielding hydrogen peroxide has been suggested. The chapter focuses on the molecular properties of the enzymes, particularly on the relationship between structure and function, but it gives a brief presentation of the biological distribution and physiological functions. In many cases, it has been possible to use copper as a built-in-molecular probe of the active site, and much structural information has been derived from the application of spectroscopic methods. The copper-containing oxidases, which utilize only half the oxidizing power of dioxygen, are the amine oxidases and galactose oxidase. Hydrogen peroxide is also formed in the oxidation of urate by the pig liver enzyme uricase, which has been reported to contain copper. |
