Purification and characterization of polyphenol oxidase from agaricus bisporus

Abstract

A polyphenol oxidase was isolated from Agaricus bisporus using ammonium sulfate precipitation, combined with DEAE-Sepharose Fast Flow chromatography and Phenyl Sepharose CL-4B chromatography. The molecular weight of the purified polyphenol oxidase was determined to be about 43 kDa with N-terminal sequence Ala-Thr-Asn-Ser-Gly-Thr-Leu-Ile-Ile-Phe by Edman degradation. The optimum temperature and pH for the polyphenol oxidase activity was 20°C and a pH of 6.5-7.0. Moreover, it was stable at 30 and 40°C over a 60 min pre-incubation time period. The Km and Vmax values of this polyphenol oxidase for catechol were 0.67 mM and 3333 U/ml min-1, respectively. In addition, following the cross linking with polyphenol oxidase, the emulsifying activity index, foam capacity, and foam stability of the whey proteins were evaluated to be modified. This work was useful to better understand polyphenol oxidase from A. bisporus, and may lead to its practical use in the future. © 2013 Copyright Taylor and Francis Group, LLC.