Pheomelanogenesis is promoted at a weakly acidic pH

作者：Wakamatsu Kazumasa; Nagao Ayano; Watanabe Miu; Nakao Kenta; Ito Shosuke

来源：Pigment Cell & Melanoma Research, 2017, 30(3): 372-377.

DOI：10.1111/pcmr.12587

<jats:title>Summary</jats:title><jats:p>The diversity of pigmentation in the skin, hair, and eyes of humans has been largely attributed to the diversity of <jats:styled-content style="fixed-case">pH</jats:styled-content> in melanosomes with an acidic <jats:styled-content style="fixed-case">pH</jats:styled-content> being proposed to suppress melanin production, especially eumelanogenesis. We previously showed that an acidic <jats:styled-content style="fixed-case">pH</jats:styled-content> greatly suppresses the late stage of eumelanogenesis after the dopachrome stage. The oxidation of tyrosine by tyrosinase in the presence of cysteine forms cysteinyldopa isomers, which are further oxidized to give rise to pheomelanin via benzothiazine intermediates. However, how those steps are controlled by <jats:styled-content style="fixed-case">pH</jats:styled-content> has not been characterized. We therefore examined whether pheomelanin synthesis is chemically promoted at an acidic <jats:styled-content style="fixed-case">pH</jats:styled-content>. We found that pheomelanin production either from dopa or tyrosine in the presence of cysteine by tyrosinase was greatest at <jats:styled-content style="fixed-case">pH</jats:styled-content> values of 5.8–6.3, while eumelanin production was suppressed at <jats:styled-content style="fixed-case">pH</jats:styled-content> 5.8. This suggests that mixed melanogenesis is chemically shifted to more pheomelanic states at a weakly acidic <jats:styled-content style="fixed-case">pH</jats:styled-content>.</jats:p>

• 出版日期2017-5