Polyphenol oxidase in<i>Azospirillum lipoferum</i>isolated from rice rhizosphere: Evidence for laccase activity in non-motile strains of<i>Azospirillum lipoferum</i>

Givaudan, Alain; Effosse, Aline; Faure, Denis; Potier, Patrick; Bouillant, Marie‐Louise; Bally, René

doi:10.1111/j.1574-6968.1993.tb06100.x

Cited by 249 publications

(45 citation statements)

References 16 publications

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“…The better-characterized enzymes are from the fungus T. versicolor and the Japanese lacquer tree R. vernicifera (hence the name laccase). Laccase activities are also found in some bacterial species [142][143][144]. The plant enzyme is involved in wound response and participates together with peroxidases in the biosynthesis of lignin [145][146][147].…”

Section: Laccasementioning

confidence: 99%

Structure and Action Mechanism of Ligninolytic Enzymes

Wong

2008

Appl Biochem Biotechnol

724

471

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Lignin is the most abundant renewable source of aromatic polymer in nature, and its decomposition is indispensable for carbon recycling. It is chemically recalcitrant to breakdown by most organisms because of the complex, heterogeneous structure. The white-rot fungi produce an array of extracellular oxidative enzymes that synergistically and efficiently degrade lignin. The major groups of ligninolytic enzymes include lignin peroxidases, manganese peroxidases, versatile peroxidases, and laccases. The peroxidases are heme-containing enzymes with catalytic cycles that involve the activation by H2O2 and substrate reduction of compound I and compound II intermediates. Lignin peroxidases have the unique ability to catalyze oxidative cleavage of C-C bonds and ether (C-O-C) bonds in non-phenolic aromatic substrates of high redox potential. Manganese peroxidases oxidize Mn(II) to Mn(III), which facilitates the degradation of phenolic compounds or, in turn, oxidizes a second mediator for the breakdown of non-phenolic compounds. Versatile peroxidases are hybrids of lignin peroxidase and manganese peroxidase with a bifunctional characteristic. Laccases are multi-copper-containing proteins that catalyze the oxidation of phenolic substrates with concomitant reduction of molecular oxygen to water. This review covers the chemical nature of lignin substrates and focuses on the biochemical properties, molecular structures, reaction mechanisms, and related structures/functions of these enzymes.

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Section: Laccasementioning

confidence: 99%

Structure and Action Mechanism of Ligninolytic Enzymes

Wong

2008

Appl Biochem Biotechnol

724

471

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“…Laccases are classified into two groups depending on their source, i.e., plant and fungal. However, diphenol oxidases (laccases) have been also identified in eubacteria [105] and insects [106]. Laccase is a copper protein and contains 4 metal ions classified into 3 types, i.e., T1, T2, T3 [102,103,107].…”

Section: Laccasementioning

confidence: 99%

Direct Electron Transfer Between Ligninolytic Redox Enzymes and Electrodes

et al. 2004

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The electrochemistry of the ligninolytic redox enzymes, which include lignin peroxidase, manganese peroxidase and laccase and possibly also cellobiose dehydrogenase, is reviewed and discussed in conjunction with their basic biochemical characteristics. It is shown that long-range electron transfer between these enzymes and electrodes can be established and their ability to degrade lignin through a direct electron transfer mechanism is discussed.

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“…In spite of the fact that laccases were found in plants [9], fungi [10], bacteria [11], and even insects [12], manly the fungal enzymes are at focus in biotechnological processes these days due to two main reasons. Firstly, pure and crude preparations of fungal laccases can be cheaply produced in preparative scale.…”

Section: Introductionmentioning

confidence: 99%

Comparative Spectroelectrochemical Studies of Lyophilized and Nonlyophilized Laccases from Cerrena unicolor Basidiomycete

et al. 2007

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The electrochemical, spectroelectrochemical, and kinetic investigations of two preparations of Cerrena unicolor laccase, lyophilized (LLAC) and nonlyophilized frozen enzymes (FLAC), were performed. It was found that the value of the redox potential of the T1 site of C. unicolor laccase is ca. 750 vs. NHE. It was also shown that one of the redox potentials of the T2/T3 cluster of C. unicolor laccase is close to 400 mV, as was previously confirmed for other blue multicopper oxidases, such as trees and fungal laccases, ascorbate oxidase, and bilirubin oxidase. Furthermore, the poor stability of both preparations, but especially of LLAC, in their reduced state was confirmed using mediated and mediatorless spectroelectrochemical studies. DET-based biocatalytic reduction of O 2 by C. unicolor laccase was only obtained, when FLAC was directly adsorbed on a spectrographic graphite electrode. Moreover, only low values of the steady-state potentials of gold and graphite electrodes modified by C. unicolor laccase were also found. Heterogeneity of the 3-D structures of laccase molecules, conformational changes, and partial denaturation of the enzyme, which appeared after enzyme isolation, purification, and especially lyophilization, were found to be the reasons for the low bioelectrocatalytic current, the high K M -value towards O 2 , and the unusual electrochemical behavior of C. unicolor laccase used in the present study. In spite of the comparable specific activity and long-term stability of both preparations in homogeneous solution, the stability of immobilized LLAC was found to be inadmissibly low for both fundamental studies and possible electrochemical applications. Indeed, FLAC is a much better source of enzyme than its lyophilized counterpart.

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Polyphenol oxidase inAzospirillum lipoferumisolated from rice rhizosphere: Evidence for laccase activity in non-motile strains ofAzospirillum lipoferum

Cited by 249 publications

References 16 publications

Structure and Action Mechanism of Ligninolytic Enzymes

Structure and Action Mechanism of Ligninolytic Enzymes

Direct Electron Transfer Between Ligninolytic Redox Enzymes and Electrodes

Comparative Spectroelectrochemical Studies of Lyophilized and Nonlyophilized Laccases from Cerrena unicolor Basidiomycete

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