The White-Rot Fungus Pleurotus ostreatus Secretes Laccase Isozymes with Different Substrate Specificities

Abstract

Four laccase isozymes (LCC1, LCC2, LCC3 and LCC4) synthesized by Pleurotus ostreatus strain V-184 were purified and characterized. LCC1 and LCC2 have molecular masses of about 60 and 65 kDa and exhibited the same pI value (3.0). Their N termini were sequenced, revealing the same amino acid sequence and homology with laccases from other microorganisms. Laccases LCC3 and LCC4 were characterized by SDS-PAGE, estimating their molecular masses around 80 and 82 kDa, respectively. By native isoelectrofocusing, their pI values were 4.7 and 4.5, respectively. When staining with ABTS and guaiacol in native polyacrilamide gels, different specificities were observed for LCC1/LCC2 and LCC3/ LCC4 isozymes.

Lignin Modifying Enzymes of Lignicolous Fungi From Rathanmahal Wildlife Sanctuary, Gujarat, India.

“…It was assayed to the procedure suggested by Mansur et al, (2003). The AAO activity was assayed spectrophotometrically, as the oxidation of veratryl (3,4dimethoxybenzyl) alcohol to veratraldehyde, monitored at 465 nm (ε = 9300 5.1-'cm-I).…”

Enhancement of TCF and ECF Bleaching Processes by Urea and Enzymatic Pretreatments: Optimization of a Laccase-Mediator Pretreatment

“…The laccase solution used in this study was the laccase-enriched extracellular liquid obtained from Pycnoporus sanguineous, where the laccase activity was 1.9 U•mL -1 . This was measured with the method of Mansur et al (2003) using ABTS as the substrate. The laccase activity unit, U, was defined as the amount of enzyme needed to produce 1 μmol of product per min at the specific test conditions.…”

Three-Dimensional X-Ray Imaging and Analysis of Fungi on and in Wood

“…Especially the white rot basidiomycetes are known to be active wood degraders since they secrete a wide range of hydrolytic and oxidative enzymes (Nicole et al, 1993) and as such are able to degrade lignin efficiently (Mansur et al, 2003). Like most other fungi, they are able to persist in dynamic, heterogeneous environments because of the capacity to take locally immobilized internal resources and remobilize these into a form capable of being reused locally or directed to new internal sinks through their hyphal network (Falconer et al, 2005).…”