肝脏去唾液酸糖蛋白受体的配体制备研究

Study on the preparation of ligand of hepatic asialoglycoprotein receptor

目的优化制备出具有高效性的肝脏去唾液酸糖蛋白受体（ASGPR）的配体半乳糖化多聚赖氨酸（Gal-PLL），为后期肝靶向性纳米液态氟碳微球超声造影剂的制备以及肝脏靶向分子成像提供依据。方法采用还原胺化法，根据各反应组分的比例不同总体分为实验组（A、B组）和对照组（C组），A、B组又分别细分成3组。A组将3种不同摩尔比的D-半乳糖和多聚赖氨酸分别与等量的足量还原剂硼氢化钠（NaBH。）进行反应，B组将相同摩尔比的D．半乳糖和多聚赖氨酸分别与3种不同量的还原剂进行反应。各组产物均经葡聚糖凝胶柱分离纯化，得到不同化合物分子质量的达峰曲线并进行分析。结果当还原剂等量时，适量减少D-半乳糖的量，分离纯化的化合物分子质量的达峰曲线提前；当D-半乳糖与多聚赖氨酸摩尔比相等时，适当减少还原剂的量，分离纯化的化合物分子质量的达峰曲线亦出现提前；当D-半乳糖与还原剂的摩尔比为1：1时，反应合成的半乳糖化多聚赖氨酸化合物与游离组分的曲线分离最为明显，且化合物的量达到最大值。结论当还原剂等量时，适量减少D-半乳糖可增强D-半乳糖与多聚赖氨酸的偶联效果；而当D-半乳糖与多聚赖氨酸摩尔比相等时，适量减少还原剂，D-半乳糖与多聚赖氨酸的偶联效果更佳；当D-半乳糖与还原剂的摩尔比为1：1时，D-半乳糖与多聚赖氨酸的偶联效果最好。D-半乳糖与多聚赖氨酸的偶联效果不仅与2者的配比相关，也与D-半乳糖与还原剂的配比相关。

Objective To optimize the preparation of high-efficiency galactocylated poly-L-lysine （Gal- PLL） ligand of the asialoglycoprotein receptor in liver, providing premise and foundation for upper prepdration of ultrasound contrast agent of liver targeted nanoseale perfluoroearbon mieroballoon and the liver targeted molecular imaging. Methods Chemical reactions of reductive amination were carried out on group A and group B according to different proportions of reaction component. Each group was subdivided into three subgroups. In group A, three different molar ratios of D-galaetose and poly-L-lysine （PLL） were compounded respectively with equivalent and sufficient reductant borohydride. In group B, identical molar ratios of D-galactose and PLL were compounded respectively with three unequal reductants borohydride. Products of each group were separated and purified by sephadex column to acquire different molecular weight distributions and the results were analyzed. Results In the condition of identical reduetant, the peak curve of compound＇s molecular weight appeared earlier when D-galactose decreased properly. In the condition of identical molar ratio of D-galactose and PLL, the peak curve of compound＇s molecular weight appeared also earlier when reduetant decreased properly. When the molar ratio of D-galactose and reductant was 1：1, the peak curve of compound Gal-PLL and free components was more obvious, and the quantity of compound Gal-PLL increased to maximum. Conclusions In the condition of identical reductant, coupling effect of D-galactose and PLL increased when D-galactose decreased properly. In the condition of identical molar ratio of D- galactose and PLL, coupling effect was better when reductant decreased properly. When the molar ratio of D- galactose and reductant was 1：1, coupling effect of them was the best. The coupling of D-galactose and PLL was related to not only the proportion of D-galactose and PLL, but also the proportion of D-galactose and reductant.