Stable isotope-labeled precursors were synthesized for an analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to elucidate the biosynthetic flow of capsaicinoids, capsinoids, and capsiconinoids. [1'-(13)C][5-(2)H]-Vanillin was prepared by the condensation of guaiacol with [(13)C]-chloroform and a D(2)O treatment. Labeled vanillylamine, vanillyl alcohol, ferulic acid, and coniferyl alcohol were prepared from the labeled vanillin. The labeled vanillylamine was converted to labeled capsaicinoid in a crude enzyme solution extracted from pungent Capsicum fruits.
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http://dx.doi.org/10.1271/bbb.110187 | DOI Listing |
Food Chem
December 2024
National Key Laboratory of Veterinary Public Health Security, College of Veterinary Medicine, China Agricultural University, Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, and Beijing Laboratory for Food Quality and Safety, Beijing 100193, China; Beijing Key Laboratory of Diagnostic and Traceability Technologies for Food Poisoning, Beijing Center for Disease Prevention and Control, Beijing 100013, China. Electronic address:
Ovalbumin (OVA) is a high-risk allergen with complex tertiary structure in food samples. Here, we developed an accurate UPLC-MS/MS-based assay to improve OVA quantitative performance in processed foods. Full-length isotope-labeled OVA proteins (OVA-I) were synthesized using stable isotope labeling by amino acids in cell culture (SILAC) technique and employed as functional internal standards to ensure similar cleavage sites between internal standards and analytes.
View Article and Find Full Text PDFPatients with stable coronary artery disease (CAD) are at an increased risk of acute myocardial infarction (AMI), particularly among older individuals. Developing a reliable model to predict AMI occurrence in these patients holds the potential to expedite early diagnosis and intervention. This study is aimed at establishing a circulating amino acid-assisted model, incorporating amino acid profiles alongside clinical variables, to predict AMI risk.
View Article and Find Full Text PDFLife Sci Alliance
March 2025
https://ror.org/0168r3w48 Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA, USA
Large multiprotein machines are central to many biological processes. However, stoichiometric determination of protein complex subunits in their native states presents a significant challenge. This study addresses the limitations of current tools in accuracy and precision by introducing concatemer-assisted stoichiometry analysis (CASA).
View Article and Find Full Text PDFAnal Chem
December 2024
State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Hong Kong SAR 999077, China.
Spatial stable isotope tracing metabolic imaging is a cutting-edge technique designed to investigate tissue-specific metabolic functions and heterogeneity. Traditional matrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) techniques often struggle with low coverage of low-molecular-weight (LMW) metabolites, which are often crucial for spatial metabolic studies. To address this, we developed a high-coverage spatial isotope tracing metabolic method that incorporates optimized matrix selection, sample preparation protocols, and enhanced post-ionization (MALDI2) techniques.
View Article and Find Full Text PDFJ Clin Med
November 2024
Core Unit Proteomics, Institute of Toxicology, Hannover Medical School, 30623 Hannover, Germany.
Mass spectrometry (MS) is the only instrumental analytical technology that utilizes unique properties of matter, that is, its mass () and electrical charge (). In the magnetic and/or electric fields of mass spectrometers, electrically charged native or chemically modified (millions) endogenous and (thousands) exogenous substances, the analytes, are separated according to their characteristic mass-to-charge ratio (/) values. Mass spectrometers coupled to gas chromatographs (GC) or liquid chromatographs (LC), the so-called hyphenated techniques, i.
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