...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Photochemistry and Photobiology, B. Biology: Official Journal of the European Society for Photobiology >Pulse radiolysis studies of ortho-quinone chemistry relevant to melanogenesis
【24h】

Pulse radiolysis studies of ortho-quinone chemistry relevant to melanogenesis

机译：与黑色素生成有关的邻醌化学的脉冲放射分解研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The contributions of pulse radiolysis towards characterisation of unstable ortho-quinones relevant to melanogenesis are reviewed. The quinones discussed include dopaquinone, the precursor of both eumelanogenesis and phaeomelanogenesis, and 5-S-cysteinyldopaquinone, an early component of the phaeomelanogenic pathway. Redox exchange between dopaquinone and 5-S-cysteinyldopa is shown to be a determinant of the balance between eumelanogenesis and phaeomelanogenesis. Ortho-quinones resulting from the oxidation of tertiary N,N-dialkylcatecholamines cyclise to redox-inactive betaines which fail to autoactivate tyrosinase. This is consistent with the dopa detected during melanogenesis catalysed by tyrosinase being formed indirectly by a combination of dopaquinone intramolecular reductive addition to form leucodopachrome (cyclodopa), followed by redox exchange between remaining dopaquinone and leucodopachrome. Rapid tautomerism of the ortho-quinone of 4-cyanomethylcatechol to a redox-inactie qinomethane likewise inhibits tyrosinase autoactivation. The incorporation of trihydric phenol moieties in melanin is modelled by the reactions of several ortho-quinones with phloroglucinol, which itself is not directly oxidised by tyrosinase due to the meta-positioning of the hydroxyl groups. The importance of a susceptibility towards nucleophilic attack as well as a propensity to undergo redox-exchange, in the chemistry of melanogenic ortho-quinones, is emphasised.
机译：综述了脉冲辐射分解对表征与黑色素生成相关的不稳定邻醌的贡献。所讨论的醌包括多巴醌，其既是Eumelanogenesis和phaeomelanogenesis的前身，又是5-S-cysteinyldopaquinone，其是phaeomelanogenic通路的早期组成部分。多巴醌和5-S-半胱氨酰多巴之间的氧化还原交换被证明是真木聚糖生成和光母细胞生成之间平衡的决定因素。 N，N-二烷基邻苯二酚叔胺氧化后生成的邻醌环氧化为无氧化还原的甜菜碱，无法使酪氨酸酶自动活化。这与酪氨酸酶催化的黑色素生成过程中检测到的多巴相吻合，酪氨酸酶是通过多巴醌分子内还原性加成形成无色多色（cyclodopa），然后在剩余的多巴醌和无色多色之间交换氧化还原而间接形成的。 4-氰基甲基邻苯二酚的邻醌与氧化还原-非活性喹诺酮的快速互变异构同样抑制酪氨酸酶的自激活。黑色素中三羟基苯酚部分的结合是通过几种邻醌与间苯三酚的反应来模拟的，间苯三酚本身由于羟基的间位而不会被酪氨酸酶直接氧化。在黑色素原位醌化学中，强调了对亲核攻击的敏感性以及进行氧化还原交换的倾向的重要性。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号