Abstract: The laccase from the fermentation liquid of Stropharia rugosoannulata strain Sr-01 was isolated and the effects of temperature,pH and metal ions on laccase activity and stability were assayed. The laccase was purified by ammonium sulfate fractional precipitation,anionic exchange chromatography on Q-Sepharose,and gel filtration chromatography on Superdex 200. The laccase activity was measured by spectrophotometry with ABTS[2,2-azinobis-（3-ethylbenzothiazoline-6-sulfonate）]as the substrate. The results showed that the specific activity of the purified laccase was 152.79 U/mg and the recovery was 35.8%. SDS-PAGE analysis demonstrated that it was a monomeric protein with the molecular weight of 40 kD. The optimal reaction temperature and pH of the laccase were 35℃ and 4.0,respectively. The laccase activity was stimulated by Mg²⁺ and Cu²⁺,whereas it was significantly inhibited by Fe²⁺,Cd²⁺ and Hg²⁺. Under the optimal reaction conditions,the specific activity of the purified laccase achieved 222.93 U/mg.

Key words: Stropharia rugosoannulata, laccase, purification, enzymatic characterization