The inhibitory activity of purified tyrosinase inhibitor
was determined as shown in Fig. I. When tyrosine
was used for the substrate of tyrosinase, inhibition was
increased approximately linearly from 0 to 80 /lg/ml
of inhibitor concentration. In the case of DOPA, the
reaction proceeded rapidly, so the concentration of
DOPA was reduced to one-third of tyrosine, and the
reaction was stopped at 5 min. A linear inhibition was
observed from 0 to 60 I'g/ml, and maximum inhibition
was 80%.