Arachidonate 15-lipoxygenase in human corneal epithelium and 12- and 15-lipoxygenases in bovine corneal epithelium: comparison with other bovine 12-lipoxygenases

Biochim Biophys Acta. 1994 Jan 20;1210(3):288-96. doi: 10.1016/0005-2760(94)90231-3.


Lipoxygenases of bovine and human corneal epithelia were investigated. The bovine epithelium contained an arachidonate 12-lipoxygenase and a 15-lipoxygenase. The 12-lipoxygenase was found in the microsomal fraction, while the 15-lipoxygenase was mainly present in the cytosol (100,000 x g supernatant). 12S-Hydroxyeicosatetraenoic acid (12S-HETE) and 15S-hydroxyeicosatetraenoic acid (15S-HETE) were identified by GC-MS and chiral HPLC. BW A4C, an acetohydroxamic acid lipoxygenase inhibitor, reduced the biosynthesis of 12S-HETE and 15S-HETE by over 90% at 10 microM. IC50 for the 12-lipoxygenase was 0.3 microM. The bovine corneal 12-lipoxygenase was compared with the 12-lipoxygenases of bovine platelets and leukocytes. All three enzymes metabolized 14C-labelled linoleic acid and alpha-linolenic acid poorly (5-16%) in comparison with [14C]arachidonic acid. [14C]Docosahexaenoic acid and [14C]4,7,10,13,16-docosapentaenoic acid appeared to be less efficiently converted by the corneal enzyme than by the platelet and leukocyte enzymes. Immunohistochemical analysis of the bovine corneal epithelium using a polyclonal antibody against porcine leukocyte 12-lipoxygenase gave positive staining. The cytosol of human corneal epithelium converted [14C]arachidonic acid to one prominent metabolite. The product co-chromatographed with 15S-HETE on reverse phase HPLC, straight phase HPLC and chiral HPLC. Our results suggest that human corneal epithelium contains a 15-lipoxygenase and that bovine corneal epithelium contains both a 15-lipoxygenase and a 12-lipoxygenase. The corneal 12-lipoxygenase appears to differ catalytically from earlier described bovine 12-lipoxygenases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid
  • Animals
  • Arachidonate 12-Lipoxygenase / analysis*
  • Arachidonate 15-Lipoxygenase / analysis*
  • Arachidonic Acid / metabolism
  • Cattle
  • Chromatography, High Pressure Liquid
  • Cornea / enzymology*
  • Epithelium / enzymology
  • Humans
  • Hydroxyeicosatetraenoic Acids / biosynthesis
  • Immunohistochemistry
  • Subcellular Fractions / enzymology


  • Hydroxyeicosatetraenoic Acids
  • Arachidonic Acid
  • 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid
  • 15-hydroxy-5,8,11,13-eicosatetraenoic acid
  • Arachidonate 12-Lipoxygenase
  • Arachidonate 15-Lipoxygenase