Immunoaffinity Intact-Mass Spectrometry for the Detection of Endogenous Concentrations of the Acetylated Protein Tumor Biomarker Neuron Specific Enolase

• Published in: Journal of proteome research 2024-08, Vol.23 (8), p.3726-3730
• Main Authors: van den Wildenberg, Sebastian A. H., Genet, Sylvia A. A. M., Broeren, Maarten A. C., van Dongen, Joost L. J., Brunsveld, Luc, Scharnhorst, Volkher, van de Kerkhof, Daan
• Format: Article
• Language: English
• Subjects: Acetylation; biomarkers; Biomarkers, Tumor - blood; Biomarkers, Tumor - metabolism; blood serum; Chromatography, High Pressure Liquid - methods; diagnostic techniques; Humans; Immunoprecipitation - methods; Letter; mass spectrometry; Mass Spectrometry - methods; neoplasms; neurons; phosphopyruvate hydratase; Phosphopyruvate Hydratase - blood; Phosphopyruvate Hydratase - isolation & purification; precipitin tests; Protein Processing, Post-Translational; proteome; qualitative analysis; ultra-performance liquid chromatography
• ISSN: 1535-3893; 1535-3907; 1535-3907
• DOI: 10.1021/acs.jproteome.4c00391

Intact-mass spectrometry has huge potential for clinical application, as it enables both quantitative and qualitative analysis of intact proteins and possibly unlocks additional pathophysiological information via, e.g., detection of specific post-translational modifications (PTMs). Such valuable and clinically useful selectivity is typically lost during conventional bottom-up mass spectrometry. We demonstrate an innovative immunoprecipitation protein enrichment assay coupled to ultrahigh performance liquid chromatography quadrupole time-of-flight high resolution mass spectrometry (UPLC-QToF-HRMS) for the fast and simple identification of the protein tumor marker Neuron Specific Enolase Gamma (NSEγ) at low endogenous concentrations in human serum. Additionally, using the combination of immunoaffinity purification with intact mass spectrometry, the presence of NSEγ in an acetylated form in human serum was detected. This highlights the unique potential of immunoaffinity intact mass spectrometry in clinical diagnostics.