EDC 是羧基和胺反应性零长度交联剂。EDC 首先与羧基发生反应，形成胺反应性 O-酰基异脲中间体，该中间体可与氨基快速反应形成酰胺键，释放异脲副产物。中间体在水性溶液中不稳定，因此两步偶联程序依赖于 N-羟基琥珀酰亚胺 (NHS) 进行稳定。如果不与胺发生反应，将导致中间体的水解、羧基的再生和 N-取代尿素的释放。副反应是形成 N-酰脲，通常仅限于位于蛋白疏水性区域的羧基。 EDC 的特点： •反应性基团：碳二亚胺 • 反应靶标：活化羧基与氨基（伯胺）偶联 • 多种偶联策略—将 EDC 单独与靶标基团反应，或包括 NHS 或磺基-NHS，以提高反应效率或稳定活性中间体，用于后续胺类反应 • 中性键—在羧基和胺之间形成中性酰胺键 • 水溶性试剂—在水性生理缓冲液中直接加入进行反应 • 可溶性反应副产物—使用水或稀释酸洗涤即可轻松去除 • 高纯度结晶试剂—用于生成高质量、活化的衍生物 • 反应性：在 pH 值为 4.7–6.0（较优）的条件下与羧基形成活性中间体，然后中间体与伯胺发生反应 产品应用： • 偶联肽和蛋白间的羧基与氨基基团 • 偶联半抗原与免疫原性载体蛋白（如将肽连接至 KLH） • 将肽抗原固定在亲和纯化抗体上 • 生成 NHS 活化、胺反应性标记化合物 • 交联蛋白与羧基包被的微珠或表面 • 使用胺反应性 Sulfo-NHS 酯活化纳米微粒 • 通过 5' 磷酸基进行 DNA 标记 EDC is a carboxyl- and amine-reactive zero-length crosslinker. EDC reacts with a carboxyl group first and forms an amine-reactive O-acylisourea intermediate that quickly reacts with an amino group to form an amide bond with release of an isourea by-product. The intermediate is unstable in aqueous solutions and so two-step conjugation procedures rely on N-hydroxysuccinimide (NHS) for stabilization. Failure to react with an amine will result in hydrolysis of the intermediate, regeneration of the carboxyl, and release of an N-substituted urea. A side reaction is the formation of an N-acylurea, which is usually restricted to carboxyls located in hydrophobic regions of proteins. Characteristics of EDC: • Reactive group:carbodiimide • Reaction target: activates carboxyl groups to conjugate to amino groups (primary amines) • Several conjugation strategies—react EDC alone with target groups or includecarbodiimide • Reactivity: Forms active intermediate with carboxyl groups at pH 4.7–6.0 (optimum), then intermediate reacts with primary amines