The inner electrons are so tightly bound that they are for all intents and purposes, immobilized when it comes to reactivity.

内部电子被紧紧地束缚着,因此无论怎样，当进行反应时，它都是固定的。

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They also have binding sites for antigen, but they are sort of two IgG type molecules bound together by another peptide chain.

同样IgA抗体表面也有与抗原结合位点,但它们就像两个IgG型分子,通过肽链相互连接

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