Abstract

In the present work crude Agaricus bisporus extract (ABE) has been prepared and characterized by its tyrosinase activity, protein composition and substrate specificity. The presence of mushroom tyrosinase (PPO3) in ABE has been confirmed using two-dimensional electrophoresis, followed by MALDI TOF/TOF MS-based analysis. GH27 alpha-glucosidases, GH47 alpha-mannosidases, GH20 hexosaminidases, and alkaline phosphatases have been also detected in ABE. ABE substrate specificity has been studied using 19 phenolic compounds: polyphenols (catechol, gallic, caffeic, chlorogenic, and ferulic acids, quercetin, rutin, dihydroquercetin, l-dihydroxyphenylalanine, resorcinol, propyl gallate) and monophenols (l-tyrosine, phenol, p-nitrophenol, o-nitrophenol, guaiacol, o-cresol, m-cresol, p-cresol). The comparison of ABE substrate specificity and affinity to the corresponding parameters of purified A. bisporus tyrosinase has revealed no major differences. The conditions for spectrophotometric determination have been chosen and the analytical procedures for determination of 1.4 × 10−4–1.0 × 10−3 M l-tyrosine, 3.1 × 10−6–1.0 × 10−4 M phenol, 5.4 × 10−5–1.0 × 10−3 M catechol, 8.5 × 10−5–1.0 × 10−3 M caffeic acid, 1.5 × 10−4–7.5 × 10−4 M chlorogenic acid, 6.8 × 10−5–1.0 × 10−3 M l-DOPA have been proposed. The procedures have been applied for the determination of l-tyrosine in food supplements, l-DOPA in synthetic serum, and phenol in waste water from the food manufacturing plant. Thus, we have demonstrated the possibility of using ABE as a substitute for tyrosinase in such analytical applications, as food supplements, medical and environmental analysis.

Highlights

  • Polyphenol oxidases (PPOs) are copper-containing enzymes that are omnipresent among bacteria, fungi, archaea, plants, and animals [1]

  • The specific activity of Agaricus bisporus extract (ABE) can be calculated as 440 U/mg of protein, while commercial A. bisporus tyrosinase (ABT) usually has the specific activity of 1000–8000 U/mg of protein

  • ABE activity was 3 times higher than for crude eggplant extract that we studied before activity for several days at 4–8 °C and for several weeks at −20 °C [22]

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Summary

Introduction

Polyphenol oxidases (PPOs) are copper-containing enzymes that are omnipresent among bacteria, fungi, archaea, plants, and animals [1]. The PPO family is composed of three different types of enzymes: catechol oxidases, laccases, and tyrosinases. Catechol oxidases catalyze the oxidation of o-diphenols to o-quinones (diphenolase activity). Laccases catalyze the oxidation of various aromatic compounds (di- and polyphenols, aminophenols and diamines). Tyrosinases catalyze the ortho-hydroxylation of monophenols (monophenolase activity) and the following diphenolase reaction. The advantages of PPOs, such as the ability to catalyze reactions without additional cofactors and to use dissolved oxygen for the oxidation of phenolic compounds, are widely used for PPO analytical applications [2]

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