Alfalfa Contains Substantial 9-hydroperoxide Lyase Activity and a 3Z:2E-enal Isomerase

FEBS Lett. 1999 Jan 25;443(2):201-4. doi: 10.1016/s0014-5793(98)01706-2.


Fatty acid hydroperoxides formed by lipoxygenase can be cleaved by hydroperoxide lyase resulting in the formation of short-chain aldehydes and omega-oxo acids. Plant hydroperoxide lyases use 13- or 9-hydroperoxy linoleic and linolenic acid as substrates. Alfalfa (Medicago sativa L.) has been reported to contain a hydroperoxide lyase specific for 13-hydroperoxy linoleic and linolenic acid only. However, in addition to 13-hydroperoxide lyase activity we found substantial 9-hydroperoxide lyase activity in alfalfa seedlings as well. The specific activity for 9-hydroperoxy fatty acids was about 50% of the activity for the 13-isomers. Furthermore, alfalfa seedlings contain a 3Z:2E-enal isomerase that converts the 3Z-enal products to their 2E-enal isoforms.

MeSH terms

  • Aldehyde-Lyases / isolation & purification
  • Aldehyde-Lyases / metabolism*
  • Chromatography, Ion Exchange
  • Hydro-Lyases
  • Mass Spectrometry
  • Medicago sativa / enzymology*
  • Substrate Specificity
  • cis-trans-Isomerases / isolation & purification
  • cis-trans-Isomerases / metabolism*


  • Aldehyde-Lyases
  • 9-hydroperoxide lyase
  • Hydro-Lyases
  • (3Z)-(2E) enal isomerase
  • cis-trans-Isomerases