Amano Masato, Kobayashi Naoki, Yabuta Masayuki, Uchiyama Susumu, Fukui Kiichi
Biologics Technology Research Laboratories, Daiichi Sankyo Co, Ltd., 1-12-1, Shinomiya, Hiratsuka-shi, Kanagawa 254-0014, Japan.
Anal Chem. 2014 Aug 5;86(15):7536-43. doi: 10.1021/ac501300m. Epub 2014 Jul 11.
Although oxidation of methionine and tryptophan are known as popular chemical modifications that occur in monoclonal antibody (mAb) molecules, oxidation of other amino acids in mAbs has not been reported to date. In this study, oxidation of the histidine residue in a human immunoglobulin gamma (IgG) 1 molecule was discovered for the first time by mass spectrometry. The oxidation of a specific histidine located at the CH2 domain of IgG1 occurred under light stress, but it was not observed under heat stress. With the forced degradation study using several reactive oxygen species, the singlet oxygen was attributed to a reactive source of the histidine oxidation. The reaction mechanism of the histidine oxidation was proposed on the basis of the mass spectrometric analysis of IgG1 oxidized in deuterium oxide and hydrogen heavy oxide.
虽然甲硫氨酸和色氨酸的氧化是单克隆抗体（mAb）分子中常见的化学修饰，但迄今为止尚未报道mAb中其他氨基酸的氧化情况。在本研究中，首次通过质谱法发现了人免疫球蛋白γ（IgG）1分子中组氨酸残基的氧化。位于IgG1 CH2结构域的特定组氨酸在光照胁迫下发生氧化，但在热胁迫下未观察到。通过使用几种活性氧进行强制降解研究，单线态氧被认为是组氨酸氧化的反应源。基于在氧化氘和氢重氧化物中氧化的IgG1的质谱分析，提出了组氨酸氧化的反应机制。
