Occurrence, Sequences, and Biological Function

Laccase is widely distributed in plants and fungi. Laccase from higher plants, found in various species of the Chinese, Vietnamese, and Japanese lacquer trees, has been extensively investigated (9). The biological function of laccase in these trees is well understood. The laccase of the lacquer trees (Rhus sp.) is found in white latex, which contains phenols. After injury of the tree, these are oxidized by dioxygen to radicals, which spontaneously polymerize, building a protective structure that closes the wound. 

Ascorbate oxidase is found in higher plants, but cucumber, Cucumis sativus, and green zucchini squash, Cucurbita pepo medullosa, are the most common sources (29). The immunohistochemical localization of ascorbate oxidase in green zucchini reveals that ascorbate oxidase is distributed ubiquitously over vegetative and reproductive organs in all specimens examined (50). Primary structures of ascorbate oxidase from cucumber, C. sativus (51), pumpkin, Cucurbita sp. Ebisu Nankin (52), and zucchini, C.pepo medullosa (53), have recently been reported. 

Ceruloplasmin is present in the plasma of all mammals examined and in birds. The amino-acid sequence of human ceruloplasmin has been determined by protein sequencing techniques (57) and later by cDNA sequencing (58). Recently, the primary structure of rat cerulo- 

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Occurrence, Sequences, and Biological Function Molecular and Spectroscopic Properties X-Ray Structure of Ascorbate Oxidase... 

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