Kupfer – ein “modernes” Bioelement

Abstract

Kupfer ist ein bioessentielles Element, das in den beiden relevanten Oxidationsstufen I und II einzigartige chemische Eigenschaften aufweist. Biochemische, molekularbiologische und medizinische Erkenntnisse einerseits sowie die Synthese und Untersuchung niedermolekularer “Modell”‐Komplexverbindungen andererseits haben in den letzten Jahren zu wesentlichen Fortschritten bei der Erforschung der teilweise überraschenden Biochemie dieses Spurenelements geführt. Auffallend, jedoch aufgrund des chemischen und des vermuteten evolutionsgeschichtlichen Hintergrundes nachvollziehbar, sind die Funktionen von proteingebundenem Kupfer vor allem im Metabolismus von O2 und N/O‐Verbindungen (NO2−, N2O) sowie seine häufige Assoziation mit oxidierenden organischen und anorganischen Radikalen wie etwa Tyrosyl, Semichinonen, Superoxid‐Ionen oder Nitrosyl‐Radikalen.

The Phenoxy/Phenol/Copper Cation: A Minimalistic Model of Bonding Relations in Active Centers of Mononuclear Copper Enzymes

“…[1][2][3][4][5] For several decades, the nature of coppercontaining active sites has been intensively studied by many research groups because of the unusual coordination geometries of copper ions, their outstanding redox potentials, absorption spectra, and electron paramagnetic resonance features, as well as their interactive role with other metal ions. Progress in metalloprotein biochemistry has profited a great deal from bioinorganic research: for nearly three decades now, a considerable body of knowledge has been accumulated from studies on the properties of small synthetic copper complexes that serve as model systems designed to mimic particular structural and/or functional aspects of their biological paragons.…”

Electron-rich salen-type Schiff base complexes of Cu(II) as catalysts for oxidation of cyclooctene and styrene with tert-butylhydroperoxide: A comparison with electron-deficient ones

“…Copper Schiff base complexes are amongst the most versatile catalysts known for oxygenation reactions. The role played by copper ions in the active sites of a large number of metalloproteins has stimulated efforts to design and characterize copper complexes as models for a better understanding of biological systems [9][10][11]. Studies of the non-enzymatic oxygenation reactions have contributed to the understanding of the oxygenase-catalyzed reactions [12][13][14].…”

Bifunctional Polyphenol Oxidases: Novel Functions in Plant Pigment Biosynthesis

“…[1] PPOs can be divided into tyrosinases, catechol oxidases, and laccases, all belonging to the copper type-3 proteins containing binuclear copper centers. [2] Tyrosinases are bifunctional PPOs, which catalyze hydroxylation of phenols to o-diphenols (EC 1.14.18.1; monophenol: monooxygenase) and their subsequent oxidation to o-quinones (EC 1.10.3.1; o-diphenol: oxygen oxidoreductase). Catechol oxidases catalyze only the latter reaction.…”