Investigation of the intracellular transport of tyrosinase and tyrosinase related protein (TRP)-1. The effect of endoplasmic reticulum (ER)-glucosidases inhibition.

Melanin biosynthesis is completely inhibited in the B16 melanoma cells following their incubation with inhibitors of the two ER glucosidases. This is primarily due to the inactivation of tyrosinase. Under the same conditions, the DOPA-oxidase activity of TRP-1 was only partially affected.

Inhibition of N-glycan processing in B16 melanoma cells results in inactivation of tyrosinase but does not prevent its transport to the melanosome.

Tyrosinase is the key enzyme in melanin biosynthesis, catalyzing multiple steps in this pathway. The mature glycoprotein is transported from the Golgi to the melanosome where melanin biosynthesis occurs. In this study, we have investigated the effects of inhibitors of N-glycan processing on the synthesis, transport, and catalytic activity of tyrosinase.