Kinetic study of sinephrine oxidation by mushroom tyrosinase.

Mushroom tyrosinase catalyzes the oxidation of sinephrine showing a marked lag period during appearance of adrenochrome and simultaneously adrenaline accumulation in the reaction medium can be detected. The adrenaline accumulation follows a sigmoidal curve until a constant level of adrenaline is reached when the system is in the steady-state. These experimental results agree with a model of enzymatic catalysis that includes the chemical evolution of adrenoquinone and permit us to explain these phenomenon as well as the influence that enzyme and sinephrine concentration present on the lag period and the level of adrenaline accumulated in the steady-state.