Which enzyme stimulates melanocytes to produce melanin?

• A. Tyrosinase
• B. Keratinase
• C. Elastase
• D. Lipase

Answer: (A)

The enzyme that stimulates melanocytes to produce melanin is tyrosinase. Tyrosinase is crucial in the melanin biosynthetic pathway, as it catalyzes the initial steps of melanin production, including the conversion of the amino acid tyrosine to dopa and then to dopaquinone. This enzymatic activity is essential for the pigmentation process, as melanin is the pigment responsible for the color of skin, hair, and eyes.

In contrast, keratinase is involved in breaking down keratin, a structural protein in the skin and hair, rather than stimulating melanogenesis. Elastase is an enzyme that breaks down elastic fibers in the skin and is more associated with skin elasticity than pigmentation. Lipase is involved in the breakdown of fats and does not relate to melanin production at all. Thus, tyrosinase is the specific enzyme that facilitates the activity of melanocytes, making it the correct choice in this context.