Enzymatic properties of the 15-lipoxygenase of human cultured keratinocytes

Barbara A Burrall, Margaret Cheung, Angela Chiu, Edward J. Goetzl

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Abstract

The arachidonic acid 15-lipoxygenase or linoleic acid co-6 lipoxygenase of human neonatal foreskin cultured keratinocytes converts arachidonic acid to 15-hydroxy-eicosatetraenoic acid and linoleic acid to 13-hydroxy-linoleic acid. A mean of 93% of the 15-lipoxygenase activity in sonicates of cultured keratinocytes was recovered in the 400,000 × g supernatant, attesting to the cytosolic localization of this enzyme. Optimal 15-lipoxygenase activity in the 400,000 × g supernatant was expressed at pH 6.7-7.3 and in the presence of calcium at a concentration of 2 mM or higher. Keratinocyte 15-lipoxygenase metabolized arachidonic acid (Km = 10.6 μM) and linoleic acid (Km = 9.5μM) with similar efficiency. Nordihydroguaiaretic acid and 5,8,11,14-eicosatetraynoic acid both inhibited the conversion of arachidonic acid to 15-HETE with respective 50% inhibitory concentrations of 2.0 μM and 0.9 μM, while ATP, GTP, and cyclic AMP had no effect on activity at pH 6.8-7.2. The enzymatic properties of human keratinocyte 15-lipoxygenase thus resemble those of PMN leukocyte 15-lipoxygenase and the mediators generated may contribute to the regulation of cutaneous sensation and inflammation.

Original languageEnglish (US)
Pages (from-to)294-297
Number of pages4
JournalJournal of Investigative Dermatology
Volume91
Issue number4
StatePublished - Oct 1988

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ASJC Scopus subject areas

  • Dermatology

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