The Involvement of Superoxide and Trivalent Copper in the Galactose Oxidase Reaction
Until the present work, Cu(I) and Cu(II) were considered to be the only valence states of copper which are involved in the various cuproenzymic reactions. In the investigations to be summarized here we have obtained the first direct evidence that Cu(III), or some mono-copper species which behaves like it, is a catalytically active intermediate in an enzymic reaction, in this case that catalyzed by galactose oxidase. In addition, the role of superoxide in the galactose oxidase reaction has been clarified to a greater extent than has been the case for most other enzymic reactions in which superoxide has been implicated. When we began this work, we certainly did not anticipate all these results, especially the involvement of Cu(III). Thus, before beginning a detailed summary of the work, it seems appropriate to briefly discuss some of our reasons for studying this enzyme, and to point out the mechanistic dilemma which faced us when we began.
KeywordsRedox Potential Induction Period Alcohol Oxidation Redox Buffer Enzymic Group
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