TYR and freckles: In addition, it has been believed that excessively active tyrosinase leads to the accumulation of melanin in the human skin, which results in various common skin diseases, such as freckles, melasma, and melanosis (Ullah et al., 2019a; Ullah et al., 2019b; Butt et al., 2019; Haldys and Latajka, 2019; Huang et al., 2019; Lee et al., 2019).