Abstract
The enzyme in Pleurotus cornucopiae var. citrinopileatus which produces yellow pigment from L-DOPA was isolated from the fruit body and characterized. The enzyme was purified from fruit body homogenate to electrophoretic homogeneity by ammonium sulfate precipitation, anion exchange chromatography and gel-filtration. The molecular weight of the purified enzyme was estimated to be 19 kDa by SDS-PAGE and 350 kDa by HPLC-GPC. The purified enzyme was stable between pH 5 to 8 and at temperatures up to 28℃; maximum activity was observed at 28℃ and pH 8. Enzyme activity was considerably inhibited by Co^<2+>, Fe^<2+>, Hg^+, Pb^<2+>, and metal ion chelator EDTA. The enzyme can use L-DOPA and dopamine as substrates with Km values of 1.2 and 1.1 mM, respectively. However, the enzyme could not utilize tyrosine and catechol, which are usual tyrosinase substrates.
