β-elimination and peptide bond hydrolysis:: Two distinct mechanisms of human IgG1 hinge fragmentation upon storage
β-elimination and peptide bond hydrolysis:: Two distinct mechanisms of human IgG1 hinge fragmentation upon storage
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DOI：
10.1021/ja0705994
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发表时间：
2007-06-06
影响因子：
15
通讯作者：
Vlasak, Josef
中科院分区：
文献类型：
--
作者：
Cohen, Steven L.;Price, Colleen;Vlasak, Josef
我们扩大了对人IgG1单抗铰链区降解的理解。首先，我们的数据更准确地证实了先前提出的IgG1重链C(220)DKTHTC铰链序列中CO-NH肽键的水解。其次，我们提供了相邻重链S219-C220键被不同机制断裂的证据。S219-C220的裂解随着pH的升高(pH>；7)变得更加明显，轻链-重链硫醚键的形成也变得更加明显，这是另一种尚不清楚的IgG1降解产物。仔细应用生物分析方法和质谱学提供了强有力的证据，证明β消除机制在解释S219-C220裂解和硫醚连接产物的形成中发挥了核心作用。
We expand the understanding of hinge-region degradation of human IgG1 monoclonal antibodies. First, our data more accurately confirm previously proposed hydrolysis of the CO-NH peptide bonds within the IgG1 heavy chain C(220)DKTHTC hinge sequence. Second, we provide evidence that the adjacent heavy chain S219-C220 bond is cleaved by a different mechanism. The cleavage of S219-C220 becomes more pronounced with elevated pH (pH > 7) as does the formation of light-chain-heavy-chain thioether linkage, another IgG1 degradation product whose mechanism has remained unknown. Careful application of bioanalytical methods and mass spectrometry provide strong evidence for a central role of a beta-elimination mechanism to account for the S219-C220 cleavage as well as the formation of the thioether linkage product.