Quantitative Urinary Proteome Analysis for Biomarker Evaluation in Chronic Kidney Disease

作者：Justyna Siwy, Eric Schiffer, Korbinian Brand, Gerhard Schumann, Kasper Rossing, Christian Delles, Harald Mischak, Jochen Metzger · 发表于：Journal of Proteome Research · 年份：2008 · DOI：10.1021/pr800401m · 被引用次数：263 · 研究领域：Advanced Proteomics Techniques and Applications、Mass Spectrometry Techniques and Applications、Hormonal and reproductive studies

A limitation of proteomic methods with respect to their clinical applicability is the lack of possibilities to directly deduce the amount of a protein or peptide from a particular mass spectrometry (MS) spectrum. For quantification of chronic kidney disease (CKD)-specific urinary polypeptides in capillary electrophoresis coupled with mass spectrometry (CE-MS), we compared signal intensity calibration methods based on either urinary creatinine or stable isotope labeled synthetic marker analogues (absolute quantification) with those based on ion counting using highly abundant collagen fragments as nonmarker references (relative quantification). Our results indicate that relative quantification of biomarker excretion based on ion counts in reference to endogenous "housekeeping" peptides is sufficient for the determination of urinary polypeptide levels. The calculation of absolute concentrations via exogenous stable isotope-labeled peptide standards is of no additional benefit.