This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Lulai, E. C. Articles by Zimmerman, D. C. Search for Related Content PubMed PubMed Citation Articles by Lulai, E. C. Articles by Zimmerman, D. C. Agricola Articles by Lulai, E. C. Articles by Zimmerman, D. C.

Articles

Metabolism of Linoleic Acid by Barley Lipoxygenase and Hydroperoxide Isomerase ¹

Department of Cereal Chemistry, United States Department of Agriculture, Science and Education Administration, Agricultural Research, North Dakota State University, Fargo, North Dakota 58105, Department of Biochemistry, North Dakota State University, Fargo, North Dakota 58105

The oxidation of linoleic acid in incubation mixtures containing extracts of barley lipoxygenase and hydroperoxide isomerase, and the production of these enzymes in quiescent and germinated barley, were investigated. The ratio of 9-hydroperoxylinoleic acid to 13-hydroperoxylinoleic acid was higher for incubation mixtures containing extracts of quiescent barley than for mixtures containing extracts of germinated barley; production of 13-hydroperoxylinoleic acid from germinated barley exceeded that of quiescent barley. Hydroperoxy metabolites of linoleic acid were converted to 9-hydroxy-10-oxo-cis-12-octadecenoic acid, 13-hydroxy-10-oxo-trans-11-octadecenoic acid, and small amounts of 11-hydroxy-12,13-epoxy-cis-9-octadecenoic acid and 11-hydroxy-9,10-epoxy-cis-13-octadecenoic acid whether quiescent or germinated barley was the enzyme source; a fifth product, 13-hydroxy-12-oxo-cis-9-octadecenoic acid was formed only when germinated barley was the enzyme source.

Lipoxygenase was readily extracted by buffer, but hydroperoxide isomerase was bound in a catalytically active state to the insoluble barley grist and was efficiently extracted only when Triton X-100 was included in the extraction buffer. Hydroperoxide isomerase was localized in the embryo of quiescent barley, but it was present in the embryo, acrospire, and in small but concentrated amounts in the rootlet of germinating barley. The levels of both lipoxygenase and hydroperoxide isomerase increased through the thirteenth day of germination.

³ Present address: Jos. Schlitz Brewing Co., P.O. Box 614, Milwaukee, WI 53201

¹ Published with approval of the director, North Dakota Agricultural Experiment Station, Fargo, ND 58105 as Journal Series No. 1112.

This article has been cited by other articles:

				B. Bakan, M. Hamberg, L. Perrocheau, D. Maume, H. Rogniaux, O. Tranquet, C. Rondeau, J.-P. Blein, M. Ponchet, and D. Marion Specific Adduction of Plant Lipid Transfer Protein by an Allene Oxide Generated by 9-Lipoxygenase and Allene Oxide Synthase J. Biol. Chem., December 22, 2006; 281(51): 38981 - 38988. [Abstract] [Full Text] [PDF]