Kappa-casein suppresses melanogenesis in cultured pigment cells

The effects of bovine milk proteins on melanogenesis in B16 cells were examined. Both whey protein isolate and casein exhibited depigmenting properties. Among the major protein components of milk--including beta-lactoglobulin, alpha-lactalbumin, alpha-, beta-, and kappa-casein--only kappa-casein exhibited the depigmenting effect. However, the carboxyl terminal peptide of kappa-casein, glycomacropeptide, did not show this activity. Also, kappa-casein promoted the proliferation of the cells and inhibited the activity of tyrosinase in the cells. These results indicate that kappa-casein acts as a melanogenesis-suppressing modulator.