title: Radiometric solvent-partitioning assay for screening cocaine hydrolases and measuring cocaine levels in milligram tissue samples.
abstract: To permit rapid screening and characterization of novel cocaine hydrolases, as well as accurate measurement of cocaine levels in small samples of tissue, a radiometric assay was developed. The assay is based on selective, organic solvent partition of [3H]benzene-labeled cocaine or of [3H]benzoic acid liberated during enzymatic hydrolysis. With dilute samples the assay can be conducted entirely in scintillation vials and quantitated by addition of appropriate aqueous buffer and toluene-based fluor, making phase separation unnecessary. In this way, several hundred samples can be assayed in an afternoon, nanogram quantities of enzyme can be characterized without prior purification, and cocaine concentrations can be accurately measured in milligram samples of tissue after administration of [3H]cocaine in vivo.
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic and Foundation for Medical Research, 200 First St. SW, Rochester, MN 55905, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Brimijoin
authors.forename: Maryann L
authors.initials: ML
authors.lastname: Shen
authors.forename: Hong
authors.initials: H
authors.lastname: Sun
mesh_terms: D000818:Animals; D019817:Benzoic Acid / Q000032:analysis*; D002091:Butyrylcholinesterase / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods; D003042:Cocaine / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D012588:Scintillation Counting / Q000379:methods*; D012680:Sensitivity and Specificity; D012997:Solvents; D013696:Temperature; D014018:Tissue Distribution; D014316:Tritium
chemical_list: D012997:Solvents; D014316:Tritium; D019817:Benzoic Acid; D006867:Hydrolases; D002091:Butyrylcholinesterase; D003042:Cocaine