Comprehensive metabolome analysis of intracellular metabolites in cultured cells.

Capillary electrophoresis mass spectrometry (CE-MS) can measure the intracellular amount of highly polar and charged metabolites; liquid chromatography mass spectrometry (LC-MS) can quantify hydrophobic metabolites. A comprehensive metabolome analysis requires independent sample preparation for LC-MS and CE-MS. Here, we present a protocol to prepare for sequentially analyzing the metabolites from one sample.

Comprehensive Dipeptide Profiling and Quantitation by Capillary Electrophoresis and Liquid Chromatography Coupled with Tandem Mass Spectrometry.

Dipeptides have attracted much attention as post-amino acids with physical properties and functions different from those of amino acids. However, a given dipeptide cannot be distinguished by mass spectrometry from its structural isomer with an opposite amino acid binding order unless these isomers are separated before introduction, which complicates the comprehensive analysis of dipeptides. Herein, a novel analytical platform for dipeptide analysis by capillary electrophoresis tandem mass spectrometry and liquid chromatography tandem mass spectrometry is developed.

Adenosine leakage from perforin-burst extracellular vesicles inhibits perforin secretion by cytotoxic T-lymphocytes.

Extracellular vesicles (EVs) in the tumor microenvironment facilitate intercellular communication. Cancer cell-derived EVs act as an immunosuppressor by transporting cargos and presenting transmembrane proteins. By contrast, CD8+ cytotoxic T-lymphocytes (CTLs) exert anti-cancer cytotoxicity via the pore-forming protein perforin.

The use of a double coaxial electrospray ionization sprayer improves the peak resolutions of anionic metabolites in capillary ion chromatography-mass spectrometry.

Recently, ion chromatography coupled with mass spectrometry has been used for the determination of anionic metabolites. However, connection with a mass spectrometer in this method is not straightforward because backpressure produced by the addition of a make-up solution often affects the peak resolutions of the target metabolites. To overcome this problem, we developed a capillary ion chromatography-mass spectrometry method utilizing a double coaxial electrospray ionization sprayer.