Laccases and their occurrence in prokaryotes

Abstract

Laccases are copper-containing proteins that require O(2) to oxidize phenols, polyphenols, aromatic amines, and different non-phenolic substrates by one-electron transfer, resulting in the formation of reactive radicals. Although their specific physiological functions are not completely understood, there are several indications that laccases are involved in the morphogenesis of microorganisms (e.g., fungal spore development, melanization) and in the formation and/or degradation of complex organic substances such as lignin or humic matter. Owing to their high relative non-specific oxidation capacity, laccases are useful biocatalysts for diverse biotechnological applications. To date, laccases have been found only in eukaryotes (fungi, plants); however, databank searches and experimental data now provide evidence for their distribution in prokaryotes. This survey shows that laccase-like enzymes occur in many gram-negative and gram-positive bacteria. Corresponding genes have been found in prokaryotes that are thought to have branched off early during evolution, e.g., the extremely thermophilic Aquifex aeolicus and the archaeon Pyrobaculum aerophilum. Phylogenetically, the enzymes are members of the multi-copper protein family that have developed from small-sized prokaryotic azurins to eukaryotic plasma proteins.

Cylindrocladium spathiphylli de espatifilo (Spathiphyllum wallisii Rengel): detecção de enzimas extracelulares em isolados normais e alterados por temperatura

“…As lacases são produzidas por fungos, plantas superiores (36) e, também, por bactérias (11). Em fungos, elas estão envolvidas em degradação de lignina (8), produção de pigmento (12) e, também, na patogênese de plantas (18).…”

Wood production, wood technology, and biotechnological impacts

“…In nature, these enzymes are produced by many fungi and plants, but also by a few bacteria and insects , Claus 2003. Besides laccase from the lacquer tree Rhus vernificera (Johnson et al 2003), commercially available laccases are usually of fungal origin (see Table 4), most likely from white-rot and saprophytic basidiomycetes such as Trametes, Pleurotus and Agaricus species that secrete high amounts of these enzymes (Minussi (Rodríguez Couto et al 2002b, Xu 2005.…”

Studies of enzymatic oxidation of TMP-fibers and lignin model compounds by a Laccase–Mediator-System using different 14C and 13C techniques

“…are the most important lignin-degrading and lignin-polymerizing enzymes (Thurston 1994). In nature, laccases are generated by many fungi, especially white-rot fungi (mostly basidiomycetes), plants, and some bacteria (Mayer and Staples 2002;Claus 2003Claus , 2004Baldrian 2006;Hoegger et al 2006). Laccases are used in many technical processes such as in the biobleaching in the pulp and paper industry (Gutierrez et al 2009;Zhang et al 2007) and the textile industry (Galante and Formantici 2003).…”