Verification of exposure to organophosphates: Generic mass spectrometric method for detection of human butyrylcholinesterase adducts.
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)2 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.
Noort
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Business Unit Biological and Chemical Protection, TNO Defense, Security and Safety, PO Box 45, 2280 AA Rijswijk, The Netherlands. daan.noort@tno.nl
Fidder
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A
van der Schans
M J
MJ
Hulst
A G
AG
D002091:Butyrylcholinesterase / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D010755:Organophosphates / Q000032:analysis* / Q000097:blood; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
D010755:Organophosphates; D002091:Butyrylcholinesterase