神经节苷脂的红外、紫外光谱分析及其多聚体结构的原子力显微镜观测

IR/UV Spectroscopic Analysis of Gangliosides and Their Microstructures of Polymeric Aggregates Observed by AFM Technique

神经节苷脂(gangliosides,Gls)是一类含有唾液酸的酸性鞘糖脂,是神经细胞膜的重要组成成分,在生物膜中起着非常重要的生理作用。文章用红外光谱(IR)、紫外光谱(UV)、原子力显微镜(AFM)分别对以牛脑为原料,采用Folch萃取法、硅胶吸附柱层析和DEAE-Sephadex A-25离子交换柱层析得到的神经节苷脂的分子官能团和多聚体结构进行了研究。实验结果表明,从100g湿组织中获得产品为55.2mg,纯度达62.84%,其紫外光谱吸收在195nm处。通过红外光谱研究证明在提纯的产品结构中含有唾液酸分子的结构片段。利用原子力显微镜对其在水中的聚集体微观形貌进行了观察研究,发现神经节苷脂在水中呈清晰的纳米级球状或椭球状结构,经测定:神经节苷脂多聚体的大小在55～380nm之间,平均大小为(148.9±66.7)nm;高度在1.0～5.0nm之间,平均高度为(3.25±1.01)nm。该实验结果为神经节苷脂的生物活性研究以及作为神经类药物的开发利用提供了理论和实验依据。

Gangliosides, a kind of acid glycosphingolipid containing sialic acid, plays a very important physiological role in biomembrane as one of the important components of neurocyte membrane. They were extracted from bovine brain by the Folch method and purified by silica gel and DEAE-Sephadex A-25 column chromatograph. Their molecular functional groups and microstructures of polymeric aggregates were studied by infrared spectrum（IR）, ultraviolet spectrum （UV）and atomic force microscope （AFM）. The experimental results indicate that： 55.2 mg of Gls from 100 g of wet bovine brain had a certain purity, 62.84%. And their UV absorption spectra appeared at 195 nm, near to the results reported by other peoples. Compared with the IR spectra of sialic acid, the experimental results showed that the structures of the products had the units of sialic acid. In order to investigate the aggregate structures of ganglioside. AFM technique was applied in water, and the results showed that gangliosides can form spherical or ellipsoidal structures in water. It was determined that the size of polymeric aggregates of gangliosides varies between 55 and 380 nm, the average size is （148. 9±66.7） nm; the height is between 1.0 and 5.0 nm, and the average height is （3. 25±1.01） nm. The experimental results provide a theoretical and experimental basis for investigating biological activity and the exploitation and utilization of neural drugs.