Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas 66047.
Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, Kansas 66047.
J Pharm Sci. 2019 Oct;108(10):3372-3381. doi: 10.1016/j.xphs.2019.06.007. Epub 2019 Jun 16.
Oxidation of therapeutic proteins (TPs) can lead to changes in their pharmacokinetics, biological activity and immunogenicity. Metal impurities such as iron are known to increase oxidation of TPs, but nanoparticulate metals have unique physical and chemical properties compared to the bulk material or free metal ions. Iron oxide nanoparticles (IONPs) may originate from equipment used in the manufacturing of TPs or from needles during injection. In this study, the impact of IONPs on oxidation of a model protein, rat growth hormone (rGH), was investigated under chemical stress. Hydrogen peroxide (HO)- and 2,2'-azobis (2-methylpropionamidine) dihydrochloride oxidized methionine residues of rGH, but unexpectedly, oxidation was suppressed in the presence of IONPs compared to a phosphate buffer control. Fourier transform infrared spectroscopy indicated splitting of the α-helical absorbance band in the presence of IONPs, whereas circular dichroism spectra showed a reduced α-helical contribution with increasing temperature for both rGH and rGH-IONP mixtures. The results collectively indicate that IONPs can increase the chemical stability of rGH by altering the kinetics and preference of amino acid residues that are oxidized, although the changes in protein secondary structure by IONPs may lead to alterations of physical stability.
治疗性蛋白质（TPs）的氧化会导致其药代动力学、生物活性和免疫原性发生变化。已知金属杂质如铁会增加 TPs 的氧化，但与块状材料或游离金属离子相比，纳米颗粒金属具有独特的物理和化学性质。氧化铁纳米颗粒（IONPs）可能来自于 TPs 制造过程中使用的设备，也可能来自于注射时的针头。在这项研究中，研究了 IONPs 在化学应激下对模型蛋白大鼠生长激素（rGH）氧化的影响。过氧化氢（HO）和 2,2'-偶氮双（2-甲基丙脒）二盐酸盐氧化 rGH 的蛋氨酸残基，但出人意料的是，与磷酸盐缓冲液对照相比，IONPs 的存在抑制了氧化。傅里叶变换红外光谱表明，在 IONPs 的存在下，α-螺旋吸收带发生分裂，而圆二色性光谱显示，随着温度的升高，rGH 和 rGH-IONP 混合物的α-螺旋贡献减少。这些结果共同表明，IONPs 可以通过改变被氧化的氨基酸残基的动力学和偏好来提高 rGH 的化学稳定性，尽管 IONPs 对蛋白质二级结构的改变可能导致物理稳定性的改变。
