A homodimeric laccase with unique characteristics from the yellow mushroom Cantharellus cibarius.
The aim of the present study was to isolate a laccase from fruiting bodies of the yellow mushroom Cantharellus cibarius. The fruiting body extract was subjected to a purification protocol that involved ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel and Con A-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. The laccase was unadsorbed on DEAE-cellulose and Affi-gel blue gel and adsorbed on Con A-Sepharose. The laccase was composed of two identical subunits each with a molecular mass of 46 kDa. The laccase exhibited a temperature-dependent rise in activity over the temperature range 20-50 degrees C. When the temperature was raised above 60 degrees C there was a fall in enzyme activity. The enzyme manifested maximal activity at pH 4. At and above pH 6 there was a dramatic reduction in activity. The unique features of this fruiting body laccase compared with previously reported mycelial laccases include homodimeric nature, a distinctive N-terminal sequence, a higher optimal pH, and adsorption on only ConA-Sepharose among the various chromatographic media tested.
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Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. biochemistry@cuhk.edu.hk
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D000595:Amino Acid Sequence; D001487:Basidiomycota / Q000201:enzymology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D019281:Dimerization; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013696:Temperature
D042845:Laccase