Naldi M, Giannone F A, Baldassarre M, Domenicali M, Caraceni P, Bernardi M, Bertucci C
Centro Interdipartimentale di Ricerche Biotecnologiche, Bologna, Italy.
Centro di Ricerca Biomedica Applicata (CRBA), Bologna, Italy and Department of Surgical and Medical Sciences, University of Bologna, Bologna, Italy.
Eur J Mass Spectrom (Chichester). 2013;19(6):491-6. doi: 10.1255/ejms.1256.
A relatively fast analytical method for the identification and quantification of the post-transcriptional changes (PTCs) occurring in circulating human serum albumin (HSA) was developed. HSA is the most abundant protein in plasma and it represents the main determinant of plasma oncotic pressure, thus being the main modulator of fluid distribution between body compartments. Cirrhotic patients have low levels of HSA. Moreover, recent studies have demonstrated that during liver cirrhosis HSA presents PTCs affecting its properties. The HSA isoforms derived from these modifications could represent promising biomarkers for liver disease. Human plasma samples were collected from a cirrhotic patient (CH) and from an aged-matched non- cirrhotic subject (CT), purified by reverse-phase chromatography and analysed by an electrospray ionization quadrupole time-of-flight (ESI-Q-ToF) spectrometer. The deconvoluted ESI mass spectra from healthy subjects were all characterized by peaks attributed to mercaptoalbumin, nitrosylated, cysteinylated, glycated and N- terminal truncated HSA isoforms. The relative abundance of each isoform was derived and transformed into a relative per cent amount and the results were compared to those obtained analysing HSA from a CH plasma. The method was validated in terms of intra-day and inter-day reproducibility, both for quantitative results and PTCs molecular weight determination. The optimized method resulted in being effective in disclosing changes in HSA isoforms relative abundance and then it could be used for the systematic screening of cirrhotic patients to identify promising new biomarkers for liver diseases.
开发了一种相对快速的分析方法，用于鉴定和定量循环人血清白蛋白（HSA）中发生的转录后变化（PTC）。HSA是血浆中含量最丰富的蛋白质，是血浆胶体渗透压的主要决定因素，因此是身体各腔室间液体分布的主要调节因子。肝硬化患者的HSA水平较低。此外，最近的研究表明，在肝硬化过程中，HSA会出现影响其性质的PTC。这些修饰产生的HSA异构体可能是肝病的有前景的生物标志物。从一名肝硬化患者（CH）和一名年龄匹配的非肝硬化受试者（CT）采集人血浆样本，通过反相色谱法纯化，并用电喷雾电离四极杆飞行时间（ESI-Q-ToF）光谱仪进行分析。来自健康受试者的去卷积ESI质谱均以归因于巯基白蛋白、亚硝基化、半胱氨酸化、糖基化和N端截短的HSA异构体的峰为特征。得出每种异构体的相对丰度，并将其转化为相对百分比量，然后将结果与分析CH血浆中HSA获得的结果进行比较。该方法在日内和日间重现性方面均得到验证，包括定量结果和PTC分子量测定。优化后的方法有效地揭示了HSA异构体相对丰度的变化，因此可用于对肝硬化患者进行系统筛查，以识别有前景的肝病新生物标志物。
