Program

Poster Presentations

Day 3, June 12（Fri.）　　Room P (5F 501+502)

3P-34

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Identification of unknown selenium metabolites in gut bacteria by isotopic pattern screening

(¹Chiba Univ., ²Chiba Univ., ³Chiba Univ.)
^oYoshikazu Yamagishi¹, Kazuaki Takahashi², Sayaka Nagasawa^1,3, Hirotaro Iwase¹, Yasumitsu Ogra^1,3

Selenium (Se) consists of six naturally occurring isotopes, i.e., 74Se (0.9 %), 76Se (9.4 %), 77Se (7.6 %), 78Se (23.8 %), 80Se (49.6 %), and 82Se (8.7 %), and exists in selenoenzymes (selenoproteins), Se-containing proteins and selenometabolites in biota. However, liquid chromatography hyphenated with inductively coupled plasma mass spectrometry (LC-ICP-MS), the primary technique for Se speciation, is difficult to identify unknown selenometabolites, thus, a new analytical technique of qualitative analysis is expected. In this study, we demonstrate an isotope pattern screening (IPS) technique for the identification of Se-containing compounds by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS). Se-containing compounds in biological matrices, including blood, urine, plant extracts, and culture media, were specifically detected by IPS. Then, we successfully identified a novel selenometabolite in the culture medium of gut bacteria exposed to Se-methylselenocysteine (MeSeCys) by IPS. IPS with ESI-MS could become a novel conventional technique for the identification of unknown selenometabolites.

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