Abstract
Two chromatographic forms of laccase c1 and c2 were purified approximately 225-fold from the extracellular culture fluid of ligninolytic cultures of Dichomitus squalens, using DEAE-Sepharose and Mono-Q fast protein liquid chromatography. Each homogeneous laccase (c1 and c2) has a molecular mass of approximately 66 kDa as determined by SDS-PAGE. Both forms are glycoproteins, and each contains four copper atoms per molecule of protein. The first 20 amino acids of the N-terminal sequences of these two laccases are identical and are similar to those of laccases from other lignin- degrading fungi. The electronic absorption spectra of these laccases exhibit bands at 610 and 330 nm, indicative of type I and type III copper. The EPR spectrum of laccase c1 exhibits bands indicative of type I and type II copper. Each laccase oxidizes a variety of phenolic substrates, has a pH optimum of 3.0 for the oxidation of 2,6-dimethoxyphenol, and is inhibited strongly by fluoride and azide.
Original language | English (US) |
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Pages (from-to) | 349-355 |
Number of pages | 7 |
Journal | Archives of Biochemistry and Biophysics |
Volume | 353 |
Issue number | 2 |
DOIs | |
State | Published - May 15 1998 |
Keywords
- Basidiomycete
- Dichomitus squalens
- Fungi
- Lignin degradation
- Multicopper oxidase
- Phanerochaete chrysosporium
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology