Effect of 2,3,4-trihydroxyacetophenone (2,3,4-THAP) and 2,4,5-trihydroxybutyrophenone (2,4,5-THBP) on the rate of DL-DOPA oxidation by mushroom tyrosinase
Co-Authors:
Kahn, V., Department of Food Science, Agricultural Research Organization, Volcani Center, POB 6, Bet Dagan 50250, Israel
Zakin, V., Department of Food Science, Agricultural Research Organization, Volcani Center, POB 6, Bet Dagan 50250, Israel
Abstract:
Various concentrations of 2,3,4-trihydroxyacetophenone (2.3,4-THAP) and 2,4,5-trihydroxybutyrophenone (2,4,5-THBP) have a synergistic effect on the rate of DL-3,4-dihydroxyphenylalanine (DL-DOPA) oxidation by mushroom tyrosinase as measured by absorbance at 475 nm. The synergism results from the ability of dopaquinone to nonenzymatically oxidize 2,3,4-THAP and 2,4,5-THBP to the corresponding o-quinone. Moreover, various concentrations of 2,3,4-THAP and 2,4,5-THBP prevent the enzymatic conversion of DL-DOPA to DOPA-melanin, probably due to the ability of these trihydroxyphenols to interact nonenzymatically with dopaquinone.