title: 2-Arachidonoylglycerol is a substrate for butyrylcholinesterase: A potential mechanism for extracellular endocannabinoid regulation.
abstract: 2-Arachidonoylglycerol (2-AG) is a component of the endocannabinoid receptor pathway and is primarily hydrolyzed by monoacylglycerol lipase (MAGL) in vivo. We found that the non-specific serine esterase, butyrylcholinesterase (BChE), can hydrolyze 2-AG with reasonable affinity and may present a new compensatory mechanism for endocannabinoid regulation. In vitro hydrolysis reactions of 2-AG with equine BChE were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) positive/negative electrospray ionization (ESI±) to measure the formation of arachidonic acid (AA) and the loss of 2-AG over time (min). The resulting Michaelis-Menten approximations reveal that BChE has affinity towards 2-AG in phosphate buffer at neutral pH (7.4). The calculated Vmax, Km and kcat were 12.1nmols(-1), 57.5μM, and 0.074s(-1), respectively, which produced a diffusion-controlled rate of association (kcat/Km) of 1.3×10(3)M(-1)s(-1). Human BChE 2-AG hydrolysis was measured by immunoprecipitating BChE from fresh plasma and monitoring 2-AG loss and AA formation over time. These findings show that BChE can hydrolyze 2-AG which may be evidence of a more specific role for BChE in endocannabinoid regulation.
authors.affiliation: Pfizer Global Research and Development, Groton Laboratories, 558 Eastern Point Rd., Groton, CT 06340, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Barricklow
authors.forename: Matthew
authors.initials: M
authors.lastname: Blatnik
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001095:Arachidonic Acids / Q000378:metabolism*; D002091:Butyrylcholinesterase / Q000378:metabolism*; D063388:Endocannabinoids / Q000378:metabolism*; D005989:Glycerides / Q000378:metabolism*; D006736:Horses / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007700:Kinetics; D008994:Monoacylglycerol Lipases / Q000378:metabolism
chemical_list: D001095:Arachidonic Acids; D063388:Endocannabinoids; D005989:Glycerides; D016718:Arachidonic Acid; C094503:glyceryl 2-arachidonate; D008994:Monoacylglycerol Lipases; D002091:Butyrylcholinesterase
keywords: 2-Arachidonoylglycerol (2-AG); Arachidonic acid (AA); Butyrylcholinesterase (BChE); Endocannabinoids; Hydrolysis; Monoacylglycerol lipase (MAGL)