Journal of Chemical Ecology

, Volume 33, Issue 5, pp 963–970

Biosynthesis of Tiglic, Ethacrylic, and 2-Methylbutyric Acids in a Carabid Beetle, Pterostichus (Hypherpes) californicus


    • Department of Chemistry and Chemical BiologyStevens Institute of Technology
  • Xiaogang Wu
    • Department of Chemistry and Chemical BiologyStevens Institute of Technology
  • Kipling W. Will
    • ESPM-Division of Insect BiologyUniversity of California

DOI: 10.1007/s10886-007-9276-3

Cite this article as:
Attygalle, A.B., Wu, X. & Will, K.W. J Chem Ecol (2007) 33: 963. doi:10.1007/s10886-007-9276-3


Tiglic, 2-methylbutyric, and ethacrylic acids are found in the pygidial gland defensive fluid of many carabid beetles. By injecting a deuterium-labeled precursor into the carabid beetle Pterostichus (Hypherpes) californicus, and analyzing the defensive fluid by gas chromatography/mass spectrometry, we were able to demonstrate that tiglic and ethacrylic acids are biosynthesized from isoleucine via 2-methylbutyric acid. Moreover, we observed that the injection of l-isoleucine induces an increased production of tiglic acid in P. californicus. A strong primary kinetic isotope effect was found to operate in the dehydrogenation step of 2-methylbutyric acid to tiglic and ethacrylic acids. Consequently, ethacrylic acid was found to preferentially accumulate the deuterium labeling from [2,3,4,4-2H4]isoleucine during our biosynthetic experiments.


BiosynthesisDefensive allomonesTiglic acid2-Methylbutyric acidEthacrylic acidIsoleucineCarabid beetlesPterostichus (Hypherpes) californicusCarabidae

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© Springer Science+Business Media, LLC 2007