Stability and activity of a phenol oxidase from the ligninolytic fungus Pleurotus ostreatus

Palmieri, Gianna; Giardina, Paola; Marzullo, Liberato; Desiderio, Bianca; Nitti, Gianpaolo; Cannio, Raffaele; Sannia, Giovanni

doi:10.1007/bf00205066

Cited by 137 publications

(81 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This work complements and extends recent reports (9,10,16) that demonstrated the production of multiple laccase isoforms in the Basidiomycete white rot fungus P. ostreatus.…”

Section: Discussionsupporting

confidence: 90%

See 1 more Smart Citation

A Novel White Laccase from Pleurotus ostreatus

Palmieri

Giardina

Bianco

et al. 1997

Journal of Biological Chemistry

328

208

View full text Add to dashboard Cite

Two laccase isoenzymes (POXA1 and POXA2) produced by Pleurotus ostreatus were purified and fully characterized. POXA1 and POXA2 are monomeric glycoproteins with 3 and 9% carbohydrate content, molecular masses of about 61 and 67 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, of about 54 and 59 kDa by gel filtration in native conditions, and of 61 kDa by matrix-assisted laser desorption ionization mass spectrometry (only for POXA1) and pI values of 6.7 and 4.0, respectively. The N terminus and three tryptic peptides of POXA1 have been sequenced, revealing clear homology with laccases from other microorganisms, whereas POXA2 showed a blocked N terminus. The stability of POXA2 as a function of temperature was particularly low, whereas POXA1 showed remarkable high stability with respect to both pH and temperature.Both enzymes oxidize syringaldazine and ABTS (2, 2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) together with a variety of different substituted phenols and aromatic amines with the concomitant reduction of oxygen, but POXA1 is unable to oxidize guaiacol. Both enzymes were strongly inhibited by sodium azide and thioglycolic acid but not by EDTA.UV/visible absorption spectra, atomic adsorption, and polarographic data indicated the presence of 4 copper atoms/mol of POXA2 but only one copper, two zinc, and one iron atoms were found/mol of POXA1.The neutral pI and the anomalous metal content of POXA1 laccase render this enzyme unique in its structural characteristics. The lack of typical absorbance at 600 nm allows its classification as a "white" laccase.

show abstract

“…This work complements and extends recent reports (9,10,16) that demonstrated the production of multiple laccase isoforms in the Basidiomycete white rot fungus P. ostreatus.…”

Section: Discussionsupporting

confidence: 90%

“…The two purified proteins, POXA1 and POXA2, appeared to be homogeneous when analyzed by SDS-PAGE, isoelectric focusing, and gel filtration chromatography. The two more acidic phenol oxidases, POXB1 and POXB2, were not further purified, whereas the POXC isoenzyme was found to correspond to the previously fully characterized enzyme (10,16).…”

Section: Resultsmentioning

confidence: 80%

A Novel White Laccase from Pleurotus ostreatus

Palmieri

Giardina

Bianco

et al. 1997

Journal of Biological Chemistry

328

208

View full text Add to dashboard Cite

show abstract

“…Most laccases are monomeric glycoproteins showing a molecular mass of between 50 and 80 kDa (49,52). The pI of C. rigida laccases (pH 3.9) are in the acidic range reported for laccases from other white rot fungi, including P. eryngii and P. ostreatus (pI 2.9 to 4.7) (38,41) and Pycnoporus cinnabarinus (pI 3.7) (16). The N-terminal sequence of C. rigida laccases shows identities of Ͼ70% with those from Trametes trogii laccase (80%) (GenBank accession number AJ294820), basidiomycete PM1 (76%) (10), T. versicolor laccase II (72%) (6), Trametes villosa laccase 1 (72%) (53), and Pycnoporus cinnabarinus (71%) (16), whereas it is quite different from those of other white rot fungi such as Pleurotus eryngii lacase II (31%) (38) and Agaricus bisporus Lcc1 and Lcc2 (28 and 24%, respectively) (44).…”

Section: Discussionmentioning

confidence: 77%

Induction, Isolation, and Characterization of Two Laccases from the White Rot BasidiomyceteCoriolopsis rigida

Saparrat

Guillén

Arambarri

et al. 2002

Appl Environ Microbiol

120

View full text Add to dashboard Cite

Previous work has shown that the white rot fungus Coriolopsis rigida degraded wheat straw lignin and both the aliphatic and aromatic fractions of crude oil from contaminated soils. To better understand these processes, we studied the enzymatic composition of the ligninolytic system of this fungus. Since laccase was the sole ligninolytic enzyme found, we paid attention to the oxidative capabilities of this enzyme that would allow its participation in the mentioned degradative processes. We purified two laccase isoenzymes to electrophoretic homogeneity from copper-induced cultures. Both enzymes are monomeric proteins, with the same molecular mass (66 kDa), isoelectric point (3.9), N-linked carbohydrate content (9%), pH optima of 3.0 on 2,6-dimethoxyphenol (DMP) and 2.5 on 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), absorption spectrum, and N-terminal amino acid sequence. They oxidized 4-anisidine and numerous phenolic compounds, including methoxyphenols, hydroquinones, and lignin-derived aldehydes and acids. Phenol red, an unusual substrate of laccase due to its high redox potential, was also oxidized. The highest enzyme affinity and efficiency were obtained with ABTS and, among phenolic compounds, with 2,6-dimethoxyhydroquinone (DBQH 2 ). The presence of ABTS in the laccase reaction expanded the substrate range of C. rigida laccases to nonphenolic compounds and that of MBQH 2 extended the reactions catalyzed by these enzymes to the production of H 2 O 2 , the oxidation of Mn 2؉ , the reduction of Fe 3؉ , and the generation of hydroxyl radicals. These results confirm the participation of laccase in the production of oxygen free radicals, suggesting novel uses of this enzyme in degradative processes.Lignin is an aromatic heteropolymer of phenyl-propanoid units which confers structural rigidity to woody plant tissues and protects them from microbial attack (25). To depolymerize and mineralize lignin, white rot fungi have developed a nonspecific oxidative system including several extracellular oxidoreductases, low-molecular-weight metabolites, and activated oxygen species (47). The ability of white rot fungi to degrade a wide number of organopollutants is in part due to the action of this nonspecific system (42). Extracellular enzymes involved in the degradation of lignin and xenobiotics by white rot fungi include several kinds of laccases (34, 49), peroxidases (8, 33), and oxidases producing H 2 O 2 (20,32,50).The enzymatic composition of the ligninolytic system depends on the fungal species, with laccase being the common component (24,43). For this reason, a wide number of studies have focused on demonstrating the participation of laccase in significant ligninolytic events which were first attributed to other enzymes of the ligninolytic system. These events include the oxidation of nonphenolic lignin units, which comprise ca. 80% of the polymer, the generation of the H 2 O 2 required for both peroxidase activities and hydroxyl radical ( ⅐ OH) formation, and the production of Mn 3ϩ from the Mn 2ϩ pr...

show abstract

“…Extracellular laccases produced by P. ostreatus were purified from liquid cultures as previously described (8,16,17).…”

Section: Methodsmentioning

confidence: 99%

Copper Induction of Laccase Isoenzymes in the Ligninolytic Fungus Pleurotus ostreatus

Palmieri

Giardina

Bianco

et al. 2000

Appl Environ Microbiol

464

310

View full text Add to dashboard Cite

Pleurotus ostreatus is a white rot basidiomycete that produces several extracellular laccase isoenzymes, including phenol oxidase A1b (POXA1b), POXA2, and POXC. POXC was the most abundant isoenzyme produced under all of the growth conditions examined in this study. Copper was the most efficient inducer of laccase activity among the putative inducers tested. The amounts of all of the previously described laccase isoenzymes increased substantially in copper-supplemented cultures. Under these conditions expression of POX isoenzymes was regulated at the level of gene transcription. It is worth noting that poxa1b mRNA was the most abundant induced transcript at all of the growth times analyzed, and the amount of this mRNA increased until day 7. The discrepancy between the poxa1b transcript and protein amounts can be explained by the presence of a high level of the protein in P. ostreatus cellular extract, which indicated that the POXA1b isoenzyme could be inefficiently secreted and/or that its physiological activity could occur inside the cell or on the cell wall. Moreover, the POXA1b isoenzyme behaved uniquely, as its activity was maximal on the second day of growth and then decreased. An analysis performed with protease inhibitors revealed that the loss of extracellular POXA1b activity could have been due to the presence of specific proteases secreted into the copper-containing culture medium that affected the extracellular POXA1b isoenzyme.

show abstract

Stability and activity of a phenol oxidase from the ligninolytic fungus Pleurotus ostreatus

Cited by 137 publications

References 25 publications

A Novel White Laccase from Pleurotus ostreatus

A Novel White Laccase from Pleurotus ostreatus

Induction, Isolation, and Characterization of Two Laccases from the White Rot BasidiomyceteCoriolopsis rigida

Copper Induction of Laccase Isoenzymes in the Ligninolytic Fungus Pleurotus ostreatus

Contact Info

Product

Resources

About