Tyrosinase activity in reversed micelles

Abstract

The hydroxylase and oxidase activities of mushroom tyrosinase were studied in both sodium di-2-ethylhexylsulfosuccinate (AOT)/isooctane and cetyltrimethylammonium bromide (CTAB)/hexane/chloroform reversed micelles. The enzyme presented its highest activity when the water to surfactant molar ratio (W₀) was 20 for both systems. When entrapped in the AOT reversed micelles, the enzyme activity decreased with the increase in AOT concentration at a constant W₀, and the enzyme not only presented a higher reaction rate related to its oxidase activity but also a shorter lag period related to its hydroxylase activity. The relation between water activity and W₀ revealed that enzyme activity in reversed micelles was more related to the size of the micelles which was determined by W₀ and less to the water activity. Tyrosinase in CTAB reversed micelles showed potential for the analysis of o-diphenols.

• AOT
• CTAB
• polyphenol oxidase
• reversed micelles
• tyrosinase
• water activity