Electrophoretic pattern of human hairbulb tyrosinase

A small gel electrophoretic system has been developed for the study of tryosinase from human hairbulb melanocytes. Enzyme is released from the hairbulb with Triton X-100. Electrophoresis is run in 60 mm microcapillary pipettes with an internal diameter of 1.5 mm. With this technique, tyrosinase from normally pigmented brown, black, blond, and red hairbulbs gives a single band when the gel is stained with L-dopa for enzyme activity. Tryosinase from tryosinase-positive oculocutaneous albino and Hermansky-Pudlak syndrome hairbulbs gives a single L-dopa band. Neuraminidase pretreatment of the tyrosinase from normal and albino hairbulbs changes the migration of the tyrosinase band to a less anodal position. Trypsin pretreatment has no effect. We conclude that human hairbulb tyrosinase is a glycoprotein and that tyrosinase-positive albino tyrosinase has no major electrophoretic difference from normal enzyme.