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Competitive inhibition of the 5‐lipoxygenase‐catalysed linoleate oxidation by arachidonic and 5‐hydroperoxy‐eicosatetraenoic acids
Author(s) -
Olga K. Mirzoeva,
Galina F. Sud’ina,
Marina A. Pushkareva,
С. Д. Варфоломеев
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01350-4
Subject(s) - arachidonic acid , lipoxygenase , chemistry , linoleic acid , enzyme , biochemistry , michaelis–menten kinetics , fatty acid , enzyme assay
Linoleic and arachidonic acids are competing substrates for 5–1ipoxygenase from barley. When these two substrates are added simultaneously, arachidonic acid acts as a competitive inhibitor of linoleic acid oxidation with K i of 20 μM, the same value as the Michaelis constant for arachidonate oxygenation by this enzyme (22 ± 3 μM). Linoleic acid hydroperoxide accumulated in the reaction mixture does not inhibit the enzymatic process, while arachidonic acid hydroperoxy product (5–hydroperoxy–6,8,11,14–eicosatetraenoic acid) inhibits it with very low K i equal to 0.5 μM.