Laccases belong to the so-called blue-copper family of oxidases and have a broad substrate specificity. The reactions catalysed by laccases proceed by the monoelectronic oxidation of a suitable substrate molecule (phenols and aromatic or aliphatic amines) to the corresponding reactive radical. The redox process takes place with the assistance of a cluster of four copper atoms that form the catalytic core of the enzyme; they also confer the typical blue colour to these enzymes because of the intense electronic absorption of the Cu–Cu linkages. The overall outcome of the catalytic cycle is the reduction of one molecule of oxygen to two molecules of water and the concomitant oxidation of four substrate molecules to produce four radicals. These reactive intermediates can then produce dimers, oligomers and polymers.
- Laccases: blues enzymes for green chemistry.Trends Biochem. Sci. 24, 219-226. [PMID:16574262]