MetaCyc Enzyme: 9S-lipoxygenase

Gene: LOX1 Accession Number: G-14678 (MetaCyc)

Species: Avena sativa

General Background

Lipoxygenases (LOX) are nonheme iron-containing enzymes that catalyze the dioxygenation of fatty acids with a 1,4-pentadiene structure and are ubiquitous among eukaryotes. In plants, LOX enzymes are known to insert oxygen at position C-9 (9-LOX) or position C-13 (13-LOX) (counting from the carboxylate group) of linoleate and α-linolenate, the most abundant fatty acids in plant membrane lipids.

In most, if not all, of the plant species studied so far lipoxygenases are encoded by gene families [Bachmann02]. In several plants, suh as soybeans, there are three major lipoxygenase isoforms, which were named LOX1, LOX2 and LOX3.

The oxygen is inserted into one of the carbons that participate in the cis double bonds of the substrate. During the process that bond is moved to a neighboring carbon and changes to a trans configuration. So, for example, linoleate ((9Z,12Z)-octadeca-9,12-dienoate) becomes 9(S)-hydroperoxy-10(E),12(Z)-octadecadienoate via 9-LOX activity, and (13S)-HPODE via 13-LOX activity.

About This Enzyme

A cDNA was cloned from developing seeds of Avena sativa. The cDNA has an ORF of 2586 base pairs, which encodes a protein with 862 amino acids. This shares more tham 70% identity with rice lipoxygenases and belongs to type I lipoxygenase, as it does not contain chloroplast transit peptide. Type I lipoxygenases introduce a peroxide group at C9 position of linolenic and linoleic acid [Meesapyodsuk11].

Molecular Weight of Polypeptide: 97.0 kD (from nucleotide sequence)

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 28-Sep-2011 by Pujar A , Boyce Thompson Institute

Enzymatic reaction of: 9S-lipoxygenase

EC Number:

linoleate + oxygen <=> (9S)-HPODE

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: epoxy fatty acid biosynthesis


Bachmann02: Bachmann A, Hause B, Maucher H, Garbe E, Voros K, Weichert H, Wasternack C, Feussner I (2002). "Jasmonate-induced lipid peroxidation in barley leaves initiated by distinct 13-LOX forms of chloroplasts." Biol Chem 383(10);1645-57. PMID: 12452441

Meesapyodsuk11: Meesapyodsuk D, Qiu X (2011). "A peroxygenase pathway involved in the biosynthesis of epoxy Fatty acids in oat." Plant Physiol 157(1);454-63. PMID: 21784965

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.0 on Wed May 27, 2015, biocyc11.