Melanocyte peroxidase

Melanocyte peroxidase, also known as melanosomal peroxidase, is an enzyme located within the melanosomes of melanocytes that plays a significant role in the biosynthesis of melanin pigments [1, 4]. While tyrosinase is traditionally viewed as the primary rate-limiting enzyme in melanogenesis, peroxidase is crucial for the oxidative polymerization of 5,6-dihydroxyindoles into eumelanin and may also participate in the initial hydroxylation of tyrosine [1, 2]. This enzyme is a target for various depigmenting agents, as its inhibition by compounds such as methimazole, ascorbic acid, and glucocorticoids leads to reduced melanin production [1, 3]. Furthermore, peroxidase can metabolize certain phenolic compounds, such as hydroquinone, into highly reactive and cytotoxic quinones, a mechanism exploited for melanocyte-specific toxicity in treating hyperpigmentation or melanoma [1]. Despite its importance, its exact physiological role relative to tyrosinase remains a subject of scientific discussion, with some researchers proposing it as a key initiator of the pathway [1, 2].

Other names

Melanosomal peroxidasePeroxidaseTyrosinase-related protein 1 (peroxidase activity)

Inhibition of enzymatic activity to reduce melanin synthesis; oxidative activation of phenolic pro-drugs into cytotoxic quinones.