Simultaneous quantification and natural abundance δ15N analysis of protein-bound amino acids in human lung tissue by GC-C-IRMS
Year: 2026
Type: preprint
Abstract: Compound specific isotope analysis in natural abundance provides a tracer free approach to investigate metabolism, but its application to amino acids in complex human tissues remains limited by derivatization requirements and the need for high precision isotope ratio measurements. Here, we developed and validated a Gas Chromatography–Combustion–Isotope Ratio Mass Spectrometry (GC-C-IRMS) method using methyl ester–pentafluoropropionyl (Me-PFP) derivatization for simultaneous quantification and δ15N analysis of protein-bound amino acids in human lung tissues. The method provided 12 measurable chromatographic signals corresponding to 13 amino acids, with satisfactory isotopic precision from standards to biological matrices, and derivative stability for 22 days in standards and for approximately 28 days in lung cancer tissue sample at −20 °C. Application to 12 paired tumor and adjacent non-tumor samples showed negative median tumor–adjacent δ15N shifts for glycine and hydroxyproline. Exploratory histology stratified analysis further suggested opposite δ15N shifts for alanine and tyrosine between adenocarcinoma and squamous cell carcinoma. These results demonstrate the suitability of a Me-PFP GC-C-IRMS workflow for combined quantitative and natural abundance nitrogen isotopic profiling of amino acids in human lung tissues.
Source: ChemRxiv
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7213979921