Analysis of heterogeneous reaction between reducing agents and keratin fibers using Raman spectroscopy and microspectrophotometry
Analysis of heterogeneous reaction between reducing agents and keratin fibers using Raman spectroscopy and microspectrophotometry
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DOI：
10.1016/j.molstruc.2012.12.040
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发表时间：
2013-04-10
影响因子：
3.8
通讯作者：
Hori, Teruo
中科院分区：
文献类型：
--
作者：
Kuzuhara, Akio;Hori, Teruo
为了在分子水平上研究还原剂巯基乙酸（TG）和L-半胱氨酸（CYS）与角蛋白纤维上角蛋白的非均相反应，采用拉曼光谱和显微分光光度法直接分析了还原剂处理后的人发不同深度断面上的非连续-SS-含量。通过进行烫发处理，存在于皮层区域中的-SS-基团的减少部分显然是基质蛋白（IFAP）。在pH9.0条件下，人发中TG的相对浓度与不同深度处的-SS-基团的断开相对浓度基本一致，表明TG在人发中的断开-SS-模式具有Fickian型特征。我们表明，TG的扩散和断开的-SS-组一起进行，逐渐地，超出角质层区域，并朝着内部的皮质区域的处女头发样品在pH 9.0。而在pH9.0的头发样品中，不同深度的-SS-基团断开的相对浓度均小于CYS的相对浓度，表明-SS-基团断开的反应速率低于CYS向人发中的扩散速率。因此，CYS在pH 9.0时几乎不能渗透到人发的皮层区域，因为CYS的游离氨基与纤维表面的阴离子发生静电相互作用。从这些实验中，我们得出结论，与TG处理的头发相比，用CYS处理的人发损伤较小，在pH9.0条件下，CYS几乎不能渗透到人发皮层区，而且CYS的-SS-基团的断开能力很低（低于60%）。(C)2013爱思唯尔有限公司版权所有。
In order to investigate the heterogeneous reaction between reducing agents (thioglycolic acid (TG) and L-cysteine (CYS)) and keratin of on keratin fibers at the molecular level, the disconnected -SS- content of cross-sections at various depths of virgin white human hair treated with reducing agents was directly analyzed using Raman spectroscopy and microspectrophotometry. The reducing section of -SS- groups existing in the cortex region by performing the permanent waving treatment was clearly the matrix protein (IFAP). The TG relative concentration and the disconnected relative concentration of disulfide (-SS-) groups at various depths of the hair samples with pH 9.0 were in good agreement, indicating that the disconnected -SS- pattern of TG into virgin human hair was Fickian type characteristics. We demonstrated that diffusion of TG and the disconnected of -SS- groups proceeded together, gradually, beyond the cuticle region, and toward the inside of the cortex region for virgin hair samples at pH 9.0. While, the disconnected relative concentration of -SS- groups at various depths of the hair samples with pH 9.0 was less than the CYS relative concentration, indicating that the reaction rate (the disconnection of -SS- groups) was slower than the diffusion rate of CYS into human hair. Consequently, CYS hardly penetrated into the cortex region of the virgin human hair at pH 9.0, since the free amino groups of CYS electrostatically interacted with the anionic ions of the fiber surface.From these experiments, we concluded that the virgin human hair treated with CYS was less damaged as compared with the hair treated with TG, since CYS hardly penetrated into the cortex region of the virgin human hair at pH 9.0, and the disconnected ability of -SS- groups of CYS was low (60% below). (C) 2013 Elsevier B.V. All rights reserved.