Wang Ting, Samareh Afsari Hamid, Anderlot Steven, Teitelbaum Aaron M, Taub Mitchell E
Department of Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Inc, 900 Ridgebury Rd, Ridgefield, Connecticut, 06877, USA.
AAPS J. 2025 Sep 18;27(6):145. doi: 10.1208/s12248-025-01130-w.
Human α-1-acid glycoprotein (hAGP) immobilized directly on NHS ester (N-hydroxysuccinimide) activated magnetic beads (hAGP-beads) was developed as a novel tool for studying small molecule hAGP binding. This method offers a straightforward, one-step immobilization process compared to traditional biotin-streptavidin immobilization technique. The hAGP-beads system provides a rapid and convenient alternative to conventional methods like equilibrium dialysis (ED) or ultracentrifugation (UF) for assessing hAGP small molecule interactions. Characterization and evaluation of the hAGP-beads system revealed that equilibrium dissociation constant (K) values of various small molecules obtained by hAGP-beads method correlated well with those determined by ED. This result suggests that the conformation of hAGP binding site is not altered after hAGP covalently binds to magnetic beads through NHS ester conjugation. Key advantages of the hAGP-beads method include shorter assay incubation times compared to ED (~ 3 min versus 4-6 h) and the ability to quantify both free and hAGP-bound small molecule species, facilitated by simple magnetic separation. Furthermore, long-term storage tests demonstrated that hAGP-beads remain stable and retain its binding functionality at -80°C, significantly reducing the need for frequent preparations. These properties make the hAGP-beads system not only well-suited for general hAGP-related studies, such as small molecule binding, but especially advantageous for high-throughput screening applications.
直接固定在N-羟基琥珀酰亚胺（NHS）酯活化磁珠上的人α-1-酸性糖蛋白（hAGP）（hAGP-磁珠）被开发为一种研究小分子与hAGP结合的新型工具。与传统的生物素-链霉亲和素固定技术相比，该方法提供了一种直接的一步固定过程。hAGP-磁珠系统为评估hAGP与小分子的相互作用提供了一种快速便捷的替代传统方法，如平衡透析（ED）或超速离心（UF）。hAGP-磁珠系统的表征和评估表明，通过hAGP-磁珠法获得的各种小分子的平衡解离常数（K）值与通过ED测定的值相关性良好。这一结果表明，hAGP通过NHS酯共轭与磁珠共价结合后，其结合位点的构象未发生改变。hAGP-磁珠法的主要优点包括与ED相比测定孵育时间更短（约3分钟对4-6小时），并且能够通过简单的磁分离对游离和与hAGP结合的小分子种类进行定量。此外，长期储存测试表明，hAGP-磁珠在-80°C下保持稳定并保留其结合功能，显著减少了频繁制备的需求。这些特性使hAGP-磁珠系统不仅非常适合一般的hAGP相关研究，如小分子结合，而且对于高通量筛选应用尤其有利。
