Article

Copper-O2 reactivity of tyrosinase models towards external monophenolic substrates: molecular mechanism and comparison with the enzyme.

Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Straße 2, 24118 Kiel, Germany.
Chemical Society Reviews (impact factor: 28.76). 03/2011; 40(7):4077-98. DOI:10.1039/c0cs00202j pp.4077-98
Source: PubMed

ABSTRACT The critical review describes the known dicopper systems mediating the aromatic hydroxylation of monophenolic substrates. Such systems are of interest as structural and functional models of the type 3 copper enzyme tyrosinase, which catalyzes the ortho-hydroxylation of tyrosine to DOPA and the subsequent two-electron oxidation to dopaquinone. Small-molecule systems involving μ-η²:η² peroxo, bis-μ-oxo and trans-μ-1,2 peroxo dicopper cores are considered separately. These tyrosinase models are contrasted to copper-dioxygen systems inducing radical reactions, and the different mechanistic pathways are discussed. In addition to considering the stoichiometric conversion of phenolic substrates, the available catalytic systems are described. The second part of the review deals with tyrosinase. After an introduction on the occurrence and function of tyrosinases, several aspects of the chemical reactivity of this class of enzymes are described. The analogies between the small-molecule and the enzymatic system are considered, and the implications for the reaction pathway of tyrosinase are discussed (140 references).

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    Article: Crystallization and preliminary analysis of crystals of the 24-meric hemocyanin of the emperor scorpion (Pandinus imperator).
    Elmar Jaenicke, Bruno Pairet, Hermann Hartmann, Heinz Decker
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    PLoS ONE 01/2012; 7(3):e32548. · 4.09 Impact Factor
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Keywords

140 references
 
aspects
 
available catalytic systems
 
chemical reactivity
 
copper-dioxygen systems inducing radical reactions
 
different mechanistic pathways
 
enzymes
 
functional models
 
known dicopper systems mediating
 
monophenolic substrates
 
phenolic substrates
 
second part
 
Small-molecule systems
 
structural
 
subsequent two-electron oxidation
 
systems
 
trans-μ-1,2 peroxo dicopper cores
 
type 3 copper enzyme tyrosinase
 
tyrosinase models
 
tyrosinases
 

Malte Rolff