[铜（II）离子对多巴色素影响的紫外可见光谱研究]
[UV-vis spectroscopic study of the effect of Cu(II) ions on dopachrome].
作者信息
Di Jun-wei, Tu Yi-feng, Zhang Feng
机构信息
Department of Chemistry, Suzhou University, Suzhou 215006, China.
出版信息
Guang Pu Xue Yu Guang Pu Fen Xi. 2004 Jul;24(7):834-6.
The effect of Cu(II) ions on dopachrome has been studied by means of UV-Vis spectra in buffer solution at pH 6.5. Cu(II) ions markedly accelerated the rate of bleaching of dopachrome (DC) at 475 nm and simultaneously exhibited general absorption in the range of 300-800 nm in the system with oxygen removed by bubble nitrogen gas. The experimental results revealed that Cu(II) ions catalyzed not only the rearrangement of DC to yield mainly 5 ,6-dihydroxyindole-2-carboxylic acid (DHICA) on first-order kinetics with respect to DC in the first part of the reaction, but also the reaction of 5,6-dihydroxyindole (DHI) and DHICA to form indole-5, 6-quinone (IQ) and indole-5,6-quinone-2-carboxylic acid (IQCA), which would immediately polymerize to yield melanin.
在pH 6.5的缓冲溶液中，通过紫外可见光谱研究了铜（II）离子对多巴色素的影响。在通过鼓泡氮气除去氧气的体系中，铜（II）离子显著加速了多巴色素（DC）在475 nm处的褪色速率，同时在300 - 800 nm范围内呈现出一般吸收。实验结果表明，铜（II）离子不仅在反应的第一阶段催化DC重排，以一级动力学主要生成5,6 - 二羟基吲哚 - 2 - 羧酸（DHICA），而且催化5,6 - 二羟基吲哚（DHI）和DHICA反应形成吲哚 - 5,6 - 醌（IQ）和吲哚 - 5,6 - 醌 - 2 - 羧酸（IQCA），后者会立即聚合生成黑色素。
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