Oxidation of endogenous N-arachidonoylserotonin by human cytochrome P450 2U1

J Biol Chem. 2014 Apr 11;289(15):10476-10487. doi: 10.1074/jbc.M114.550004. Epub 2014 Feb 21.

Abstract

Cytochrome P450 (P450) 2U1 has been shown to be expressed, at the mRNA level, in human thymus, brain, and several other tissues. Recombinant P450 2U1 was purified and used as a reagent in a metabolomic search for substrates in bovine brain. In addition to fatty acid oxidation reactions, an oxidation of endogenous N-arachidonoylserotonin was characterized. Subsequent NMR and mass spectrometry and chemical synthesis showed that the main product was the result of C-2 oxidation of the indole ring, in contrast to other human P450s that generated different products. N-Arachidonoylserotonin, first synthesized chemically and described as an inhibitor of fatty acid amide hydrolase, had previously been found in porcine and mouse intestine; we demonstrated its presence in bovine and human brain samples. The product (2-oxo) was 4-fold less active than N-arachidonoylserotonin in inhibiting fatty acid amide hydrolase. The rate of oxidation of N-arachidonoylserotonin was similar to that of arachidonic acid, one of the previously identified fatty acid substrates of P450 2U1. The demonstration of the oxidation of N-arachidonoylserotonin by P450 2U1 suggests a possible role in human brain and possibly other sites.

Keywords: Arachidonic Acid; Cytochrome P450; Eicosanoid; Lipid Oxidation; Mass Spectrometry (MS).

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Arachidonic Acids / metabolism*
  • Brain / metabolism
  • Catalysis
  • Cattle
  • Chromatography, Liquid
  • Cytochrome P-450 Enzyme System / metabolism*
  • Cytochrome P450 Family 2
  • Erythrocytes / enzymology
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Enzymologic
  • Humans
  • Indoles / metabolism
  • Liver / enzymology
  • Magnetic Resonance Spectroscopy
  • Mass Spectrometry
  • Molecular Sequence Data
  • Oxygen / metabolism*
  • Polymerase Chain Reaction
  • Protein Binding
  • Proteomics
  • Sequence Homology, Amino Acid
  • Serotonin / analogs & derivatives*
  • Serotonin / metabolism

Substances

  • Arachidonic Acids
  • Indoles
  • arachidonoylserotonin
  • Serotonin
  • Cytochrome P-450 Enzyme System
  • CYP2U1 protein, human
  • Cytochrome P450 Family 2
  • Oxygen