title: Alfalfa contains substantial 9-hydroperoxide lyase activity and a 3Z:2E-enal isomerase.
abstract: 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.
authors.affiliation: Bijvoet Center for Biomolecular Research, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: Noordermeer
authors.forename: G A
authors.initials: GA
authors.lastname: Veldink
authors.forename: J F
authors.initials: JF
authors.lastname: Vliegenthart
mesh_terms: D000446:Aldehyde-Lyases / Q000302:isolation & purification / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D006836:Hydro-Lyases; D013058:Mass Spectrometry; D000455:Medicago sativa / Q000201:enzymology*; D013379:Substrate Specificity; D019745:cis-trans-Isomerases / Q000302:isolation & purification / Q000378:metabolism*