Site-selective conjugation to biomolecules via thiol-based chemistry is superior to the unselective modification of lysine residues, which produce a mixed product and can potentially interfere with binding affinity of the biomolecule. However, in physiological environments, the maleimide-thiol conjugation product which is the current gold-standard for site-selective thiol-conjugation can be susceptible to hydrolysis or a retro-Michael reaction via exchange with reactive thiols such as those in albumin or glutathione residues yet the degradation is relatively slow. Therefore, for in vivo studies, the maleimide-thiol conjugation proposes instability issues. The compositions and methods disclosed herein provide an alternative thiol-based linkage, one that overcomes the instability issues with conventional reagents and methods. The compositions and methods disclosed herein are useful in various contexts, for example, for 18F-labeling of peptides/proteins in the preparation of positron emission tomography (PET) probes.
基于巯基
化学的位点选择性
生物分子共轭化优于赖
氨酸残基的非选择性修饰,后者会产生混合产物并可能干扰
生物分子的结合亲和力。然而,在生理环境中,目前的
金标准位点选择性巯基
化学反应产物——马来
酰亚胺-巯基共轭物可能会受到
水解或通过与白蛋白或
谷胱甘肽残基中的反应性巯基交换而发生返Michael反应的影响,但降解相对缓慢。因此,对于体内研究,马来
酰亚胺-巯基共轭化可能存在不稳定性问题。本文所披露的组合物和方法提供了一种替代的基于巯基的连接,克服了传统试剂和方法的不稳定性问题。本文所披露的组合物和方法在各种情况下都很有用,例如,在正电子发射断层扫描(PET)探针制备中用于18F标记肽/蛋白质。