Faculty Collaboration Database

Synthesis and characterization of diazomethylarachidonyl ketone: an irreversible inhibitor of N-arachidonylethanolamine amidohydrolase. J Pharmacol Exp Ther 1998 Jul;286(1):184-90

Date

07/10/1998

Pubmed ID

9655859

Scopus ID

2-s2.0-0031847458 (requires institutional sign-in at Scopus site)   45 Citations

Abstract

N-Arachidonylethanolamine (AEA), a putative endogenous agonist of neuronal (CB1) cannabinoid receptors, is a substrate for N-arachidonylethanolamine amidohydrolase (AEA amidohydrolase), a serine amidase present in cell membranes. Following a strategy that has been used to develop inhibitors that covalently bind to the active site of serine peptidases, diazomethyl arachidonyl ketone (DAK) was synthesized and its effects on AEA amidohydrolase were determined. DAK inhibits the hydrolysis of AEA by rat brain membranes with an IC50 value of 0.5 microM. At low concentrations, DAK reduces the Vmax and increases the K(m) of the enzyme for its substrate AEA, which suggests that it is both a competitive and noncompetitive inhibitor. At higher concentrations, DAK inhibition is completely noncompetitive. DAK inhibition of membrane-associated AEA amidohydrolase is irreversible because hydrolytic activity is not restored with extensive washing or dialysis of the membranes. Furthermore, DAK inhibition is not reversible by anion exchange chromatography of the subsequently solubilized enzyme. In contrast, DAK inhibition of detergent-solubilized enzyme exhibits competitive kinetics and is reversible upon ion exchange chromatography. Exposure of C6 glioma cells to DAK results in concentration-related inhibition of AEA amidohydrolase activity in cellular membranes with an IC50 value of 0.3 microM. In summary, these studies demonstrate that DAK is an irreversible inhibitor of AEA amidohydrolase in its native membrane and provides a useful tool with which to study the role of AEA amidohydrolase in the termination of action of AEA.

Author List

Edgemond WS, Greenberg MJ, McGinley PJ, Muthian S, Campbell WB, Hillard CJ

Authors

William B. Campbell PhD Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin
Cecilia J. Hillard PhD Associate Dean, Center Director, Professor in the Pharmacology and Toxicology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Amidohydrolases
Animals
Arachidonic Acids
Cyclohexanols
Diazomethane
Dose-Response Relationship, Drug
Enzyme Inhibitors
Male
Rats
Rats, Sprague-Dawley
Tumor Cells, Cultured