title: Purification and characterization of a novel laccase from the mushroom Pleurotus nebrodensis.
abstract: A novel laccase with a molecular mass of 64 kDa and the N-terminal sequence AIGPDDTINF was isolated from fresh fruiting bodies of the mushroom Pleurotus nebrodensis. The purification protocol comprised ion exchange chromatography on DEAE-cellulose, CM-cellulose, and Q-Sepharose, and gel filtration on Superdex 75. The laccase was adsorbed on DEAE-cellulose and Q-Sepharose, but not on CM-cellulose. It demonstrated an optimal temperature of 70°C. The enzyme activity increased steadily over the temperature range 20°C-70°C. There was only a slight reduction in activity at 80°C. However, all activity disappeared following exposure to 100°C for 10 minutes. The enzyme activity changed only slightly over the pH range 3-5, with the optimum at pH 5, but underwent a precipitous decline when the pH was elevated to 6, and was undetectable at pH 8 and pH 9.
authors.affiliation: Institute of Biotechnology and Germplasmic Resource, Yunnan Academy of Agricultural Science, Kunming, China.
authors.forename: Guo-Ting
authors.initials: GT
authors.lastname: Tian
authors.forename: Guo-Qing
authors.initials: GQ
authors.lastname: Zhang
authors.forename: He-Xiang
authors.initials: HX
authors.lastname: Wang
authors.forename: Tzi Bun
authors.initials: TB
authors.lastname: Ng
mesh_terms: D000327:Adsorption; D000595:Amino Acid Sequence; D002396:Catechols / Q000737:chemistry; D002848:Chromatography, DEAE-Cellulose / Q000379:methods; D002850:Chromatography, Gel / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D004789:Enzyme Activation; D057075:Enzyme Assays / Q000379:methods; D048690:Fruiting Bodies, Fungal / Q000201:enzymology; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000737:chemistry / Q000302:isolation & purification*; D008970:Molecular Weight; D010655:Phenylenediamines / Q000737:chemistry; D020076:Pleurotus / Q000201:enzymology*; D011748:Pyrogallol / Q000737:chemistry; D020539:Sequence Analysis, Protein / Q000379:methods; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002396:Catechols; D005656:Fungal Proteins; D010655:Phenylenediamines; D011748:Pyrogallol; C004781:dimethyl-4-phenylenediamine; D042845:Laccase; C034221:catechol