熊果苷
黑素细胞
酪氨酸酶
作用机理
化学
黑色素
生物化学
酶
分子生物学
生物
体外
癌症研究
黑色素瘤
作者
Kazuhisa Maeda,Mitsunori Fukuda
出处
期刊:PubMed
日期:1996-02-01
卷期号:276 (2): 765-9
被引量:490
摘要
Arbutin, a naturally occurring beta-D-glucopyranoside of hydroquinone, is effective in the topical treatment of various cutaneous hyperpigmentations characterized by hyperactive melanocyte function. We examined the mechanism of its depigmenting action in human melanocyte cultures. Arbutin inhibited the tyrosinase activity of cultured human melanocytes at noncytotoxic concentrations. It did not affect the expression of tyrosinase mRNA. Melanin production was inhibited significantly by arbutin, as determined by measuring eumelanin radicals with an electron spin resonance spectrometer. The study of the kinetics and mechanism for inhibition of tyrosinase confirms the reversibility of arbutin as a competitive inhibitor of this enzyme. The utilization of L-tyrosine or L-dopa as the substrate suggests a mechanism involving competition with arbutin for the L-tyrosine binding site at the active site of tyrosinase. These results suggest that the depigmenting mechanism of arbutin in humans involves inhibition of melanosomal tyrosinase activity, rather than suppression of the expression and synthesis of tyrosinase.
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