Kamal U. Zaidi , Ayesha S. Ali, Sharique A. Ali
Biotechnology of Biotechnology
Tyrosinase (EC188.8.131.52) was extracted from oyster mushroom, Pleurotus ostreatus, using 100 mM potassium phosphate buffer (pH 5.8) containing 1 mM of ethylenediaminetetra acetic acid. The enzyme was purified by ammonium sulfate precipitation, followed by Sephadex G-100 and diethylaminoethyl chromatography. The purified enzyme showed a specific activity of 46.4 U/mg with 20.3 % yield. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed single peptide chain with a molecular weight of 75 kDa. The enzyme has optimum activity on pH 6.0 at 35˚ C. The kinetics parameter with L-DOPA (3,4-dihydroxy-L-phenylalanine), with a KM of 0.119 mM and Vmax of 2.97 mM. Thus, purified tyrosinase from P.ostreatus showed similarities with other tyrosinase sources. The results indicate that P.ostreatus can be a novel and better source of tyrosinase extraction due to its higher specific activity. The information offered here should help food industry in developing and using potential tyrosinase desirable efficacy and safety, and for improving food quality.