Laccase: enzyme revisited and function redefined

Abstract

One enzyme, one physiological role, that's how most scientists have traditionally looked at it but there is a growing appreciation that some enzymes "moonlight" i.e. in addition to their "primary" catalytic function, they carry other functions as well. Moonlighting refers to a protein that has multiple functions, which are not because of gene fusion; splice variants or multiple proteolytic fragments. Until recently laccases were reported from eukaryotes, e.g. fungi, plants, insect. However there is some evidence for its existence in prokaryotes, a protein with typical features of multi-copper oxidase enzyme family. The present available knowledge of its structure provides a glimpse of its plasticity, revealing a multitude of binding sites responsible for multifunctional activity. Laccase represents an example of a 'moonlighting' protein that overcomes the one gene-one structure-one function concept to follow the changes of the organism in its physiological and pathological conditions. It is wide spread in plants, where it is involved in biosynthesis of lignin; in fungi it is involved in lignin degradation, development associated pigmentation (melanin synthesis), detoxifi cation and pathogenesis, and in bacteria, laccases are involved in the synthesis of endospore coat protein (cot A).

Laccase isozymes from Ganoderma lucidum MDU-7: Isolation, characterization, catalytic properties and differential role during oxidative stress

“…Laccases (p-diphenol: dioxygen oxidoreductase; EC 1.10.3.2) are polyphenol oxidases that catalyze the oxidation of phenolic compounds with a concomitant reduction of oxygen to water [5]. Laccases are present in fungi, plants, insects and bacteria with diversified functions, such as, polymerization in plants, depolymerization and pathogenicity in fungi and bacteria [6,7]. Several studies have been focused on laccase production because of its potential application in delignification, paper bleaching, deinking of news paper, bioremediation, textile industries, biosensors, and in medical sectors [6][7][8][9][10].…”

Thermophilic laccase from xerophyte species Opuntia vulgaris

“…Laccases are also used as cleaning agents for certain water purification systems (Jaouani et al ., 2005), as catalysts for the manufacture of anti‐cancer drugs (Yaropolov et al ., 1994) and even as ingredients in cosmetics (Golz et al ., 2004) and the food industry (Selinheimo et al ., 2006). In plants, laccases are involved in the biosynthesis of lignin (Sharma and Kuhad, 2008). With such applications this enzyme can be categorized to exhibit ‘moonlighting properties’.…”

Fungal-Mediated Biodegradation of Ingredients in Personal Care Products

“…1.10.3.2) are enzymes that contain four copper atoms, in different states of oxidation (I, II, and III) [57]. They are not only restricted to WRF as they can be found also in plants and some bacteria and recently reported in green algae too [58,59]. Fungal laccases oxidize a broad range of compounds such as phenols, polyphenols, methoxysubstituted phenols, and amines [60] while reducing O 2 to H 2 O (four-electron reduction).…”