title: Purification and characterization of a novel laccase from Fomitopsis pinicola mycelia.
abstract: A novel laccase was isolated from the culture filtrate of the brown-rot fungus, Fomitopsis pinicola. Enzyme production reached its highest level after cultivation for 8 days at 25°C. The enzyme was purified by ultrafiltration, ion exchange chromatography, gelfiltration chromatography, and hydrophobic interaction chromatography. Zymography analysis of the purified enzyme showed a laccase band with a molecular mass of 92 kDa. The molecular weight of the enzyme was 92 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography. The enzyme also had an isoelectric point of 3.8. The optimum temperature and pH for enzyme activity were 80°C and 3.0, respectively. Enzyme activity was relatively stable in the pH range from 1.5 to 11.0 and at temperatures below 40°C. The N-terminal amino acid sequence of the enzyme was DTHKAEIACRFKDLG. Enzyme activity was potently inhibited by NaN3 and SDS. The enzyme showed the highest specific activity for 2,2-azino-bis(3-ethylthiazoline-6-sulfonate) (ABTS) as a substrate. The Km value of the enzyme for ABTS substrate was 0.28 mM with a Vmax value of 4.5 U/min. The enzyme degraded several recalcitrant dyes at different time intervals during decolorization. Therefore, the novel laccase from F. pinicola may be potentially useful in industry.
authors.affiliation: Department of Biotechnology, Dongguk University, Gyeongju 780-714, Republic of Korea.
authors.forename: Naomi
authors.initials: N
authors.lastname: Park
authors.affiliation: Department of Biotechnology, Dongguk University, Gyeongju 780-714, Republic of Korea. Electronic address: sspark@dongguk.ac.kr.
authors.forename: Sang-Shin
authors.initials: SS
authors.lastname: Park
mesh_terms: D000595:Amino Acid Sequence; D055453:Coriolaceae / Q000737:chemistry* / Q000201:enzymology; D004789:Enzyme Activation; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D007700:Kinetics; D042845:Laccase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D008670:Metals / Q000737:chemistry; D008970:Molecular Weight; D025282:Mycelium / Q000737:chemistry*; D054730:Protein Interaction Domains and Motifs; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D007477:Ions; D008670:Metals; D042845:Laccase
keywords: Decolorization; F. pinicola; Laccase