Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin
Diversity of human hair pigmentation as studied by chemical analysis of eumelanin and pheomelanin
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DOI：
10.1111/j.1468-3083.2011.04278.x
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发表时间：
2011-12-01
影响因子：
9.2
通讯作者：
Wakamatsu, K.
中科院分区：
文献类型：
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作者：
Ito, S.;Wakamatsu, K.
头发颜色是人类最显著的表型之一，从黑色、棕色、金色到红色。这种多样性主要来自黑-深棕色真黑色素和红-棕色现象黑色素的数量和比例。为了研究头发颜色多样性背后的化学基础，我们开发了几种化学方法来量化这两种色素。在碱性H2O2氧化作用下，吡咯-2,3,5-三羧酸（PTCA）和噻唑-2,4,5-三羧酸（TTCA）分别作为真黑素和现象黑素的标记物。经氢碘酸水解后，也可分析为4-氨基-3-羟基苯基丙氨酸（4-AHP）。利用这些方法，我们对黑色、深棕色、棕色、浅棕色、金色和红色头发（视觉表型）中真黑素和泛黑素（化学表型）的含量进行了评价。真黑素的含量依次下降，除了红头发的真黑素和真黑素含量相当外，其他头发的真黑素含量都是微量的。因此，化学表型与视觉表型密切相关。调节红发表型的基因黑素皮质素-1受体（melanocortin-1 receptor, MC1R）的基因型可预测头发黑色素以真黑色素与褐黑色素之比的对数值表达，且具有明显的剂量效应。还分析了各种低色素疾病患者的头发黑色素含量，包括hermansky - pudlak综合征、Menkes病、proopiomelanocortin缺乏症、胱氨酸病、营养不良和微量金属缺乏症。化学表型有助于评估每种疾病对色素沉着的精确影响。在人类头发的研究中，化学表型作为色素沉着的客观指标将得到越来越多的应用。
Hair colour is one of the most conspicuous phenotypes in humans, ranging from black, brown, blond to red. This diversity arises mostly from the quantity and ratio of the black-dark brown eumelanin and the reddish-brown pheomelanin. To study the chemical basis underlying the diversity of hair colour, we have developed several chemical methods to quantify those two pigments. Alkaline H2O2 oxidation affords pyrrole-2,3,5-tricarboxylic acid (PTCA) as a eumelanin marker and thiazole-2,4,5-tricarboxylic acid (TTCA) as a pheomelanin marker. Pheomelanin can also be analysed as 4-amino-3-hydroxyphenylalanine (4-AHP) after hydroiodic acid hydrolysis. Using those methods, we evaluated the contents of eumelanin and pheomelanin (the chemical phenotype) in human hairs of black, dark brown, brown, light brown, blond and red colour (the visual phenotype). Eumelanin contents decrease in that order, with a trace but constant level of pheomelanin, except for red hair which contains about equal levels of pheomelanin and eumelanin. Thus, the chemical phenotype correlates well with the visual phenotype. The genotype of melanocortin-1 receptor (MC1R), a gene regulating the red hair phenotype, is predictive of hair melanin expressed as the log value of eumelanin to pheomelanin ratio, with a dosage effect evident. Hair melanin contents were also analysed in patients with various hypopigmentary disorders including HermanskyPudlak syndrome, Menkes disease, proopiomelanocortin deficiency, cystinosis, malnutrition and trace metal deficiency. The chemical phenotype helped evaluate the precise effects of each disease on pigmentation. In studies of human hair, the chemical phenotype will find more and more application as an objective measure of pigmentation.