Program

Poster Presentations

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

3P-43

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Metabolite Profiling of the Side-Chain-to-Tail Cyclized Peptide Elcatonin Using a Software-Assisted Workflow

(LRC)
^oMinori Fukazawa, Kohei Ohnuma, Taiga Uchida, Michiko Bannai, Mariko Shibuya, Kensaku Shirai, Misato Hirano-kodaira, Masayuki Yamada

The use of osteoporosis drugs is regulated to ensure equine health and welfare in equine sports. Elcatonin is a side chain-to-tail cyclic peptide with anti-resorptive and analgesic properties. An LC-FAIMS-MS/MS method is available for parent elcatonin detection; however, its metabolites (including catabolites) have not been systematically investigated. This limited characterization is partly because elcatonin’s non-amino-acid-based cyclization is not directly supported by conventional peptide-analysis software. Here, we present a modified, software-assisted workflow for metabolite profiling of side chain-to-tail cyclic peptides. Elcatonin-derived metabolites were generated by incubating the parent peptide with equine liver lysate or plasma, followed by Oasis WCX solid-phase extraction. Extracts were analyzed by LC-HRMS/MS, and data were processed using BioPharma Finder and Compound Discoverer. A key aspect of this strategy is the representation of the cyclic moiety as a single structural block, thereby enabling analysis within standard linear-peptide workflows. Using this approach, the peptide sequence TDVGAGTP-NH₂ (the linear chain portion of elcatonin) was identified as a putative candidate based on MS/MS spectral matches to the reference standard and spectra observed in the equine liver-lysate incubation samples. Furthermore, TDVGAGTP-NH₂ was detected in horse plasma samples collected after elcatonin administration.

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