Human Serum Albumin is the most abundant protein of the plasma and displays a wide range of non-oncotic properties such as antioxidant activity, distribution in tissues and organs of binding molecules and clearance of toxic compounds. Albumin is susceptible to numerous post-translational modifications and particularly related to its free thiol group at Cys₃₄ which is the main circulating scavenger of reactive oxygen species. The characterization of these modifications is of high interest for the diagnosis and treatment of patients with liver diseases and for the structural integrity assessment of albumin as a therapeutic protein.

In this study, an ion exchange chromatographic method coupled on-line to native mass spectrometry was developed in order to bridge an effective charge variants separation method with a powerful identification technique for a detailed characterization of albumin isoforms. The chromatographic performance of the method allows the separation of 9 different isoforms that were on-line characterized by MS as oxidized, glycated, deamidated and N/C-terminal truncated forms. The method is also able to detect Cu(II) ions binding to the N-terminal site of the protein which is an important antioxidant feature of albumin. Finally, the method showed preliminary good performance parameters in term of linearity, precision and sensitivity for characterization of purified albumin as well as albumin from raw plasma for clinical and pharmaceutical purposes.

人血清白蛋白是血浆中最丰富的蛋白质，并显示出广泛的非渗透性，例如抗氧化活性，结合分子在组织和器官中的分布以及有毒化合物的清除。白蛋白易受多种翻译后修饰的影响，尤其与其在Cys ₃₄处的游离硫醇基有关，Cys ₃₄是活性氧的主要循环清除剂。这些修饰的表征对于肝病患者的诊断和治疗以及白蛋白作为治疗性蛋白的结构完整性评估非常重要。

在这项研究中，开发了一种在线耦合至天然质谱的离子交换色谱方法，以期将有效的电荷变体分离方法与功能强大的鉴定技术联系起来，以对白蛋白同工型进行详细表征。该方法的色谱性能允许分离9种不同的同工型，这些同工型通过MS在线表征为氧化，糖化，脱酰胺和N / C末端截短形式。该方法还能够检测与蛋白质N末端位点结合的Cu（II）离子，这是白蛋白的重要抗氧化剂特征。最后，该方法在线性，精密度和灵敏度方面表现出初步的良好性能参数，可表征纯化的白蛋白以及用于临床和制药目的的原始血浆中的白蛋白。