Harris R J
Analytical Chemistry Department, Genentech, Inc, South San Francisco, CA 94080, USA.
Dev Biol (Basel). 2005;122:117-27.
Structural heterogeneity of recombinant IgG1 antibodies derives from variations in conserved as well as unique structural features. Common sources of heterogeneity include Fc glycosylation, partial heavy chain C-terminal Lys processing, Fc methionine oxidation, hinge-region cleavage, and the glycation of Lys residues. Aspartate residues that are isomerized to iso-aspartate were detected by cation exchange or hydrophobic interaction chromatography for trastuzumab and omalizumab, respectively. Unpaired cysteines were detected in omalizumab using Ellman's reagent, with the thiol-containing Fab resolved using hydrophobic interaction chromatography after papain digestion. Structural variations that cause chromatographic resolution may indicate the presence of a form with reduced potency.
重组IgG1抗体的结构异质性源于保守结构特征以及独特结构特征的变化。异质性的常见来源包括Fc糖基化、重链C末端赖氨酸的部分加工、Fc甲硫氨酸氧化、铰链区裂解以及赖氨酸残基的糖基化。分别通过阳离子交换或疏水相互作用色谱法检测曲妥珠单抗和奥马珠单抗中异构化为异天冬氨酸的天冬氨酸残基。使用埃尔曼试剂在奥马珠单抗中检测到未配对的半胱氨酸，木瓜蛋白酶消化后，含硫醇的Fab通过疏水相互作用色谱法分离。导致色谱分离的结构变化可能表明存在效力降低的形式。
