Oxygen-tree copper

Laccase was discovered in 1883 by Yoshida (4), who found that the latex of the Chinese or Japanese lacquer tree rapidly hardened to a plastic in the presence of oxygen, and he attributed this to the presence of a diastase in the lacquer. A few years later Bertrand (5) further purified this enzyme and named it laccase. He suggested that laccase is a metalloprotein containing manganese and introduced the term oxidase. About 50 years later Keilin and Mann (6) demonstrated that laccase is a copper enzyme and showed that its blue color disappears reversibly upon addition of substrate. Laccase has been extensively reviewed by the researchers in this field over the last 20 years, and a representative selection is listed (3, 7-12). 

Tyrosinase or polyphenol oxidase (EC 1.14.18.1) is a bifunctional, copper-containing enzyme widely distributed on the phylogenetic tree. This enzyme uses molecular oxygen to catalyze the oxidation of monophenols to their corresponding o-diphenols (cresolase activity) as well as their subsequent oxidation to o-quinones (catecholase activity). The o-quinones thus generated polymerize to form melanin, through a series of subsequent enzymatic and nonenzymatic reactions [1-3]. 

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