Competitive Inhibition of Mushroom Tyrosinase by 4-Substituted Benzaldehydes

Abstract
A kinetic study of the inhibition of mushroom tyrosinase by 4-substituted benzaldehydes showed that these compounds behave as classical competitive inhibitors, inhibiting the oxidation of l-3,4-dihydroxyphenylalanine (l-DOPA) by mushroom tyrosinase (o-diphenolase activity). The kinetic parameter (KI) characterizing this inhibition was evaluated for all of the seven compounds assayed. Cuminaldehyde showed the most potent inhibitory activity (KI = 9 μM). It also inhibited the oxidation of l-tyrosine by mushroom tyrosinase (o-monophenolase activity) in a competitive manner. The corresponding kinetic parameter for this inhibition was evaluated (KI = 0.12 mM). Keywords: Tyrosinase; monophenolase; diphenolase; cuminaldehyde; competitive inhibitors