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RESEARCH PRODUCT

Copper-Containing Oxidases: Occurrence in Soil Microorganisms, Properties, and Applications

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Copper is an essential trace element in living systems, where it is used as a cofactor in many enzymatic redox reactions and oxygen transport. The copper-containing oxidases tyrosinase and laccase are widely distributed in soil microorganisms. Recently, progress has been made with respect to structural and catalytic data for the tyrosinase of the soil bacterium Streptomyces. The formation of eumelanins—dark polymers with multiple functionality (e.g., UV protection, immune defense)—is a well-established task of tyrosinases. An abundance of information exists on the structures and biochemical properties of fungal laccases. Many studies have demonstrated a physiological role for them in the detoxification of phenolic compounds. The existence of soil laccase activity underlines their ecological importance in the metabolic turnover of complex organic polymers such as lignin and humic matter. In ectomycorrhizal symbiotic fungi, they contribute to the nutrition of trees by mobilizing and transporting nutrients to plant roots. The specific monohydroxylase activity of tyrosinase and the high nonspecific oxidation capacity of laccase have been exploited for numerous biotechnological processes.