EPR OF MELANIN AT W BAND

各种类型的黑色素(多巴、5-S-半胱基多巴、多巴胺、DHI) 在一定的样品pH值范围内，用W波段EPR进行了研究。这个 在高频下大大增强的分辨率允许独特的 不同黑色素的G各向异性将作为以下函数进行研究 PH值。在X波段具有基本相同光谱的黑色素可以 在W波段脱颖而出。预测性目标理论帮助人们做出选择 在这些物种的假设结构之间。不同 在不同的黑色素中发现了半喹酮阴离子自由基。 在碱性条件下。这些半醌基团主要是 由于水合良好的二羟基吲哚基团。黑色素也 含有一组不是半喹酮或 半喹酮是亚胺类化合物，且随pH变化不大。这些激进分子是 与较不溶解的或浓缩的部分有关 聚合物。

Various types of melanin (DOPA, 5-S-cystienylDOPA, dopamine, DHI) at a range of sample pH values have been studied by W-band EPR. The greatly enhanced resolution at high frequency allows for the unique g-anisotropies of different melanins to be studied as a function of pH. Melanins which have essentially identical spectra at X-band can be distinguished at W-band. Predictive MO theory helps one to choose between postulated structures for these species. Different semiquinone anion radicals have been identified in different melanins under alkaline conditions. These semiquinone radicals are primarily due to dihydroxyindole groups that are well hydrated. Melanin also contains a set of free radicals which are not semiquinone or semiquinone imines and vary little with pH. These radicals are associated with the less solubilized or condensed portion of the polymer.