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Verification of exposure to organophosphates: Generic mass spectrometric method for detection of human butyrylcholinesterase adducts

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Author: Noort, D. · Fidder, A. · Schans, M.J. van der · Hulst, A.G.
Institution: TNO Defensie en Veiligheid
Source:Analytical Chemistry, 18, 78, 6640-6644
Identifier: 239480
doi: doi:10.1021/ac060954t
Keywords: Enzyme inhibition · Ethanol · Mass spectrometry · Phosphates · Plasmas · Proteins · Generic mass spectrometric · Human butyrylcholinesterase adducts · Organophosphates · Phosphylated peptides · Biochemistry · Cholinesterase · Cholinesterase inhibitor · Dichlorvos · Methylphosphonothioic acid s (2 diisopropylaminoethyl) o ethyl ester · Nerve gas · Nonapeptide · Organophosphate pesticide · Organophosphorus compound · Pepsin A · Phosphoserine · Procainamide · Proton · Sarin · Soman · Analytic method · Article · Biological monitoring · Chemical warfare · Cholinesterase inhibition · Human · Liquid chromatography · Plasma · Solid phase extraction · Spectrometer · Tandem mass spectrometry · Terrorism · Time of flight mass spectrometry · Butyrylcholinesterase · Chromatography, Liquid · Humans · Phosphoric Acid Esters · Solid Phase Extraction · Tandem Mass Spectrometry


We present a generic mass spectrometric method to verify exposure to organophosphates, based on the chemical conversion of the phosphylated peptides obtained after pepsin digestion of human butyrylcholinesterase (HuBuChE) to a common precursor peptide. After exposure of plasma to various organophosphates (nerve agents, pesticides), HuBuChE was isolated from plasma by procainamide affinity-based solid-phase extraction. Upon subsequent pepsin digestion, the respective phosphylated nonapeptides could be identified in the digests. After treatment of the pepsin digests with Ba(OH)a in the presence of a nucleophilic tag (a thiol or amine), the phosphylated nonapeptides were transformed into a common tagged nonapeptide that could be analyzed sensitively by means of LC tandem MS. So far, best results were obtained with 2-(3-aminopropylamino)ethanol as nucleophilic tag. By applying the presented method, HuBuChE inhibition can now be monitored accurately by mass spectrometry, without advance knowledge of the structure of the inhibitor. © 2006 American Chemical Society.