A novel histidine-histidine (His-His) photooxidative cross-link has been identified in an IgG4 antibody. It was formed between the side chain of a histidine residue of the antibody and histidine from the formulation buffer. The structure of the cross-link was elucidated using high performance liquid chromatography (HPLC) hyphenated to tandem mass spectrometry (MS/MS) with higher energy collisional dissociation (HCD). The cross-link was found in multiple conformations, as the location of the oxygen varied. Furthermore, the extent of cross-link formation was shown to correlate with the amount of light the antibody was exposed to as well as the solvent accessibility of each modification site.

中文翻译：

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在IgG4抗体中发现了光诱导的组氨酸-组氨酸交联。

在IgG4抗体中已鉴定出新型的组氨酸-组氨酸（His-His）光氧化交联。它在抗体的组氨酸残基的侧链和来自制剂缓冲液的组氨酸之间形成。使用高效液相色谱（HPLC）和高能碰撞解离（HCD）联用串联质谱（MS / MS）阐明了交联结构。随着氧的位置变化，发现交联具有多种构型。此外，显示出交联形成的程度与抗体所暴露的光量以及每个修饰位点的溶剂可及性相关。