Lin S Y, Duan K J, Lin T C
Department of Medical Research and Education, Veterans General Hospital-Taipei, Taiwan, Republic of China.
Methods Find Exp Clin Pharmacol. 1996 Apr;18(3):175-81.
A newly developed microscopic Fourier transform infrared (FT-IR) spectrometry combined with differential scanning calorimetry (DSC) was used to investigate the thermal response and IR spectral changes of protein structure in porcine stratum corneum (SC) after pretreatment with the skin penetration enhancers propylene glycol (PG), azone/PG, oleic acid (OA)/PG, vitamin C, and vitamin C+ OA/PG. The amide I and II bands of protein were used as probe to determine the structural transformation of protein with temperature. A reheating process was also performed. Dual effects of enhancer and temperature on the protein conformational changes of porcine SC were studied. The results indicate that the new FT-IR/DSC system can continuously determine the thermoresponsive conversion process from alpha-helix to beta-sheet in keratin structure of porcine SC pretreated with different enhancers. The thermally induced keratin conversion in protein structure of porcine SC, independent of pretreatment with skin penetration enhancers, was irreversible. The process of conformational transition in protein was found to be partially from alpha-helix to random coil structure or partially from alpha-helix to beta-sheet structure during heating. The kinetics of this conversion between first-heating and second-heating processes were significantly different; the process of conversion for all first-heated porcine SC samples during second-heating process were slower than that of porcine SC samples during first-heating process. Moreover, it was also found that the skin penetration enhancers, when present during the heating process, were able to synergistically and promotively alter the keratin conversion in protein structure of porcine SC, with the PG, OA/PG and azone/PG enhancers being the most effective.
一种新开发的显微镜傅里叶变换红外（FT-IR）光谱法结合差示扫描量热法（DSC），用于研究用皮肤渗透促进剂丙二醇（PG）、氮酮/PG、油酸（OA）/PG、维生素C以及维生素C + OA/PG预处理后猪角质层（SC）中蛋白质结构的热响应和红外光谱变化。蛋白质的酰胺I和II带用作探针，以确定蛋白质结构随温度的转变。还进行了再加热过程。研究了促进剂和温度对猪SC蛋白质构象变化的双重影响。结果表明，新的FT-IR/DSC系统可以连续测定用不同促进剂预处理的猪SC角蛋白结构中从α-螺旋到β-折叠的热响应转化过程。猪SC蛋白质结构中热诱导的角蛋白转化与是否用皮肤渗透促进剂预处理无关，是不可逆的。发现在加热过程中蛋白质构象转变过程部分是从α-螺旋到无规卷曲结构，或部分是从α-螺旋到β-折叠结构。第一次加热和第二次加热过程之间这种转化的动力学有显著差异；所有第一次加热的猪SC样品在第二次加热过程中的转化过程比第一次加热过程中的猪SC样品慢。此外，还发现皮肤渗透促进剂在加热过程中存在时，能够协同促进改变猪SC蛋白质结构中的角蛋白转化，其中PG、OA/PG和氮酮/PG促进剂最有效。
