NAD(P)H-dependent reduction of 12-ketoeicosatetraenoic acid to 12(R)- and 12(S)-hydroxyeicosatetraenoic acid by rat liver microsomes

Biochem Biophys Res Commun. 1988 Nov 15;156(3):1083-9. doi: 10.1016/s0006-291x(88)80743-5.

Abstract

The possibility that 12-keto-5,8,10,14 eicosatetraenoic acid (12-KETE) could be used as substrate by reductase(s) to generate 12-hydroxyeicosatetraenoic acid (12-HETE) was investigated using rat liver microsomes as a source of enzyme activity. Microsomes catalyzed the time-dependent reduction of 12-KETE to 12-HETE in a reaction that required NAD(P)H. The maximal specific activity of 12-HETE formation was 1.7 nmol/min/mg of protein in the presence of NADH. The reaction could not be detected in the absence of cofactor or by using heat inactivated microsomes. The identity of the 12-HETE product was established by U.V. spectroscopy and co-elution with 12-HETE in two different systems of RP-HPLC. Resolution of the methyl esters of reaction products by chromatography on chiral columns also indicated that the reduction of 12-KETE with either NADPH or NADH generated a mixture of 12(S)- and 12(R)-HETE in a ratio of about 2:1. The results demonstrate the presence of a 12-KETE reductase activity in rat liver microsomes which can form both the R and S isomers of 12-HETE.

MeSH terms

  • 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid
  • Animals
  • Arachidonic Acids / metabolism*
  • Hydroxyeicosatetraenoic Acids / biosynthesis*
  • In Vitro Techniques
  • Microsomes, Liver / metabolism*
  • NADP / pharmacology*
  • Oxidation-Reduction
  • Rats

Substances

  • 12-keto-5,8,11,13-eicosatetraenoic acid
  • Arachidonic Acids
  • Hydroxyeicosatetraenoic Acids
  • NADP
  • 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid