二价抗体片段（F (ab')2 片段）比整个 IgG 分子小，使其能够更好地渗入组织，因而有利于在 IHC 中更好地识别抗原。 使用 F (ab')2 片段还避免了与活细胞上的 Fc 受体或蛋白 A/G 的非特异性结合。

F (ab') 2 fragments have two antigen-binding (Fab) regions linked by disulfide bonds, making them divalent. The average molecular weight is approximately 110 kDa. They are used in specific applications, such as avoiding recognition of secondary antibodies by Fc receptors on live cells, or to Protein A or Protein G.

2021年7月4日 · What are F (ab) and F (ab')2 fragments? The F (ab) fragment is an antibody structure that still binds to antigens but is monovalent with no Fc portion. An antibody digested by the enzyme papain yields two F (ab) fragments of about 50 kDa each and an Fc fragment.

F（ab'）2 经略微还原可分离为两个含巯基的单价 Fab’ 片段。 Fab’ 片段的优势在于可直接通过巯基与可检测标记物发生结合，从而确保活性结合位点不受阻碍并保持活性。

Fab片段（Antigen-binding fragment）又叫做抗原结合片段，是抗体结构中可以与抗原结合的区域。 其由完整的轻链（可变区和恒定区）和部分重链结构（可变区和一个恒定区片段）组成，轻链与重链通过一个二硫键连接，…

F (ab) and F (ab')2 fragment secondary antibodies are antigen-binding fragments that are derived from full-length secondary antibodies, conventionally through enzymatic cleavage. These fragments offer several advantages over whole IgG antibodies due to their smaller size and the absence of the Fc region.

Antibody IgG structure and cleavage sites for fragmentation. Useful antibody fragments, including half-IgG, Fab, F (ab')2, and Fc, can be produced by reduction of hinge-region disulfides or digestion with papain, pepsin, or ficin proteolytic enzymes.

2024年11月27日 · F (ab) 和 (Fab')2 片段二抗有什么区别？ X-MOL学术平台旗下问答系统，汇集专家智慧，共同解决问题。 化学及相关领域的专业问题，包括实验原理、实验操作、反应路线、实验设计等，还有求职招聘及职场生涯的答疑解惑.

用哺乳动物系统表达Fab抗体片段， 可以顺利的形成二硫键，更接近天然Fab结构，活性也更高，可以更好的应用于下游科研研究，是优于大肠杆菌表 达系统的选择。

F (ab) 和 F (ab')2 片段二抗是源自全长二抗的抗原结合片段，通常通过酶促切割。 这些片段由于其片段大小较小和缺乏 Fc 区域，因此相对于完整 IgG 抗体具有几个优势。