EFFECT OF MALTOL ON THE OXIDATION OF DL-DOPA, DOPAMINE, N-ACETYLDOPAMINE (NADA), AND NOREPINEPHRINE BY MUSHROOM TYROSINASE

Maltol (3-hydroxy-2-methyl-4H-pyran-4-one) appears to inhibit the rate of oxidation of DL-DOPA, dopamine, NADA and epinephrine by tyrosinase when assayed spectrophotometrically but not when assayed polarographi cally. Maltol has an effect on the spectrum of product(s) formed when each catecholamine was oxidized by tyrosinase showing that maltol hast ens the disappearance of the quinones, possibly by conjugating with th em. Indeed, at relatively high concentrations, maltol prevented the co nversion of DL-DOPA, dopamine, and norepinephrine to their correspondi ng melanins via tyrosinase.