Oxidation Products of Tryptophan and Proline in Adipokinetic Hormones—Artifacts or Post-Translational Modifications?
Background: Adipokinetic hormones (AKHs) regulate important physiological processes in insects. AKHs are short peptides with blocked termini and Trp in position 8. Often, proline occupies position 6. Few post-translational modifications have been found, including hydroxyproline ([Hyp6]) and kynureni...
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Dokumenttypen: | Artikel |
Medientypen: | Text |
Erscheinungsdatum: | 2023 |
Publikation in MIAMI: | 21.12.2023 |
Datum der letzten Änderung: | 21.12.2023 |
Angaben zur Ausgabe: | [Electronic ed.] |
Quelle: | Life 13 (2023) 12, 2315, 1-18 |
Schlagwörter: | mass spectrometry; peptide fragmentation; hydroxyproline; kynurenine |
Fachgebiet (DDC): | 610: Medizin und Gesundheit |
Lizenz: | CC BY 4.0 |
Sprache: | English |
Förderung: | "Finanziert durch den Open-Access-Publikationsfonds der Universität Münster." |
Format: | PDF-Dokument |
URN: | urn:nbn:de:hbz:6-58918401139 |
Weitere Identifikatoren: | DOI: 10.17879/58918404847 |
Permalink: | https://nbn-resolving.de/urn:nbn:de:hbz:6-58918401139 |
Verwandte Dokumente: |
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Onlinezugriff: | 10.3390_life13122315.pdf |
Background: Adipokinetic hormones (AKHs) regulate important physiological processes in insects. AKHs are short peptides with blocked termini and Trp in position 8. Often, proline occupies position 6. Few post-translational modifications have been found, including hydroxyproline ([Hyp6]) and kynurenine. Our recent data suggest that the Hyp- and Kyn-containing AKHs occur more often than originally thought and we here investigate if they are natural or artifactual. Methods: From crude extracts of the corpora cardiaca (CC) of various insect species, AKHs were analyzed using liquid chromatography coupled to high-resolution mass spectrometry (LC-MS). Synthetic [Hyp6]-AKHs were tested in an in vivo metabolic assay. Freshly dissected Periplaneta americana and Blaberus atropos CCs (with precautions taken against oxidation) were analyzed. B. atropos CC were placed into a depolarizing saline and the released AKHs were measured. Results: Hyp was detected in several decapeptides from cockroaches. The modified form accompanied the AKH at concentrations below 7%. The [Hyp6]-AKHs of B. atropos were present in fresh CC preparations and were shown to be releasable from the CC ex vivo. Synthetic [Hyp6]-containing peptides tested positively in a hypertrehalosemic bioassay. Hydroxyprolination was also detected for Manto-CC from the termite Kalotermes flavicollis and for Tetsu-AKH of the grasshopper, Tetrix subulata. Oxidized Trp-containing forms of Nicve-AKH were found in species of the burying beetle genus Nicrophorus. Conclusions: Trp oxidation is known to occur easily during sample handling and is likely the reason for the present findings. For hydroxyprolination, however, the experimental evidence suggests endogenous processes.