PMID:9492266

Citation	Vörös, K, Feussner, I, Kühn, H, Lee, J, Graner, A, Löbler, M, Parthier, B and Wasternack, C (1998) Characterization of a methyljasmonate-inducible lipoxygenase from barley (Hordeum vulgare cv. Salome) leaves. Eur. J. Biochem. 251:36-44
Abstract	We found three methyl jasmonate-induced lipoxygenases with molecular masses of 92 kDa, 98 kDa, and 100 kDa (LOX-92, -98 and -100) [Feussner, I., Hause, B., Vörös, K., Parthier, B. & Wasternack, C. (1995) Plant J. 7, 949-957]. At least two of them (LOX-92 and LOX-100), were shown to be localized within chloroplasts of barley leaves. Here, we describe the isolation of a cDNA (3073 bp) coding for LOX-100, a protein of 936 amino acid residues and a molecular mass of 106 kDa. By sequence comparison this lipoxygenase could be identified as LOX2-type lipoxygenase and was therefore designated LOX2:Hv:1. The recombinant lipoxygenase was expressed in Escherichia coli and characterized as linoleate 13-LOX and arachidonate 15-LOX, respectively. The enzyme exhibited a pH optimum around pH 7.0 and a moderate substrate preference for linoleic acid. The gene was transiently expressed after exogenous application of jasmonic acid methyl ester with a maximum between 12 h and 18 h. Its expression was not affected by exogenous application of abscisic acid. Also a rise of endogenous jasmonic acid resulting from sorbitol stress did not induce LOX2:Hv:1, suggesting a separate signalling pathway compared with other jasmonate-induced proteins of barley. The properties of LOX2:Hv:1 are discussed in relation to its possible involvement in jasmonic acid biosynthesis and other LOX forms of barley identified so far.
Links	PubMed
Keywords	Acetates/pharmacology; Amino Acid Sequence; Base Sequence; Chromosome Mapping; Cyclopentanes/pharmacology; DNA, Complementary/isolation & purification; Gene Expression Regulation, Plant/drug effects; Hordeum/enzymology; Lipoxygenase/drug effects; Lipoxygenase/genetics; Lipoxygenase/metabolism; Molecular Sequence Data; Oxylipins; Plant Growth Regulators/pharmacology; Plant Leaves/enzymology; Sequence Analysis, DNA; Sorbitol/pharmacology
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
HORVU:LOX21	enables	GO:0016165: linoleate 13S-lipoxygenase activity	ECO:0000314: direct assay evidence used in manual assertion		F		Seeded From UniProt	complete
HORVU:LOX21	involved_in	GO:0009753: response to jasmonic acid	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
HORVU:LOX21		GO:0016165: lipoxygenase activity	ECO:0000314:		F		LOX2:Hv:1 protein was expressed in Escherichia coli. Lipoxygenase activity in the bacterial extracts was determined spectrophotometrically using linoleic, linolenic, and arachidonic acid as substrates. As seen in figure 5, HPLC was used to demonstrate products of the oxygenation of arachidonic acid.	complete CACAO 8403
HORVU:LOX21		GO:0009753: response to jasmonic acid stimulus	ECO:0000314:		P		Figure 7B	complete CACAO 8404

References

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