IUBMB Enzyme Nomenclature


Accepted name: hydroperoxide dehydratase

Reaction: (9Z,11E,15Z)-(13S)-hydroperoxyoctadeca-9,11,15-trienoate = (9Z,15Z)-(13S)-12,13-epoxyoctadeca-9,11,15-trienoate + H2O

Glossary: 13-hydroperoxylinolenoate = (9Z,11E,15Z)-(13S)-hydroperoxyoctadeca-9,11,15-trienoate

Other name(s): hydroperoxide isomerase; linoleate hydroperoxide isomerase; linoleic acid hydroperoxide isomerase; HPI; (9Z,11E,14Z)-(13S)-hydroperoxyoctadeca-9,11,14-trienoate 12,13-hydro-lyase; (9Z,11E,14Z)-(13S)-hydroperoxyoctadeca-9,11,14-trienoate 12,13-hydro-lyase [(9Z)-(13S)-12,13-epoxyoctadeca-9,11-dienoate-forming]; allene oxide synthase; AOS

Systematic name: (9Z,11E,15Z)-(13S)-hydroperoxyoctadeca-9,11,15-trienoate 12,13-hydro-lyase [(9Z,15Z)-(13S)-12,13-epoxyoctadeca-9,11,15-trienoate-forming]

Comments: Acts on a number of unsaturated fatty-acid hydroperoxides, forming the corresponding allene oxides. The product of the above reaction is unstable and is acted upon by EC, allene-oxide cyclase, to form the cyclopentenone derivative (15Z)-12-oxophyto-10,15-dienoate (OPDA), which is the first cyclic and biologically active metabolite in the jasmonate biosynthesis pathway [3]. The enzyme from many plants belongs to the CYP-74 family of P450 monooxygenases [4].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Esselman, W.J. and Clagett, C.O. Products of linoleic hydroperoxide-decomposing enzyme of alfalfa seed. J. Lipid Res. 15 (1974) 173-178. [PMID: 4208994]

2. Hamberg, M. Mechanism of corn hydroperoxide isomerase - detection of 12,13(S)-oxido-9(Z),11-octadecadienoic acid. Biochim. Biophys. Acta 920 (1987) 76-84.

3. Hamberg, M. Biosynthesis of 12-oxo-10,15(Z)-phytodienoic acid: identification of an allene oxide cyclase. Biochem. Biophys. Res. Commun. 156 (1988) 543-550. [PMID: 3178850]

4. Laudert, D., Pfannschmidt, U., Lottspeich, F., Holländer-Czytko, H. and Weiler, E.W. Cloning, molecular and functional characterization of Arabidopsis thaliana allene oxide synthase (CYP 74), the first enzyme of the octadecanoid pathway to jasmonates. Plant Mol. Biol. 31 (1996) 323-335. [PMID: 8756596]

[EC created 1992, modified 2008]

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