title: Copper and cadmium increase laccase activity in Pleurotus ostreatus.
abstract: Addition of copper (0.5-5 mM) or cadmium (1-5 mM) to the white rot fungus Pleurotus ostreatus cultivated in liquid nitrogen-limited medium for 12 days increased the activity of laccase. The addition of 2 mM Cd led to an 18.5-fold increase of activity, 1 mM Cu increased the activity eight-fold. When added earlier than 12 days, the activation of laccase was delayed (Cu) or decreased (Cd). Ag, Hg, Pb, Zn, and H(2)O(2) decreased laccase activity. To study the effect on native enzymes, purified laccase was incubated with Cd, Cu, and Hg. The addition of Hg decreased the activity of laccase immediately and reduced the temporal stability of the enzyme, while the addition of Cu (0.05-50 mM) increased both enzyme activity and stability. Laccase extracted at different stages of straw colonisation differed in its response to heavy metals.
authors.affiliation: Laboratory of Biochemistry of the Wood-rotting Fungi, Institute of Microbiology, ASCR, Vídenská 1083, 14220 4, Prague, Czech Republic. baldrian@biomed.cas.cz
authors.forename: Petr
authors.initials: P
authors.lastname: Baldrian
authors.forename: Jirí
authors.initials: J
authors.lastname: Gabriel
mesh_terms: D001709:Biotechnology; D002104:Cadmium / Q000494:pharmacology*; D003300:Copper / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal; D006861:Hydrogen Peroxide / Q000494:pharmacology; D042845:Laccase; D019216:Metals, Heavy / Q000494:pharmacology; D010088:Oxidoreductases / Q000187:drug effects* / Q000302:isolation & purification / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism; D020076:Pleurotus / Q000201:enzymology* / Q000254:growth & development
chemical_list: D019216:Metals, Heavy; D002104:Cadmium; D003300:Copper; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D042845:Laccase; D010544:Peroxidases; C051129:manganese peroxidase