Mice treated with a nontoxic dose of chlorpyrifos oxon have diethoxyphosphotyrosine labeled proteins in blood up to 4 days post exposure, detected by mass spectrometry

Wei Jiang, Ellen G. Duysen, Oksana Lockridge

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity is an established biomarker of exposure to organophosphorus poisons (OP). Inhibition of activity is due to covalent binding of the OP to the active site serine. Mass spectrometry has made it possible to monitor OP exposure by analyzing OP adducts on tyrosine in proteins that have no active site serine. Our goal was to test the hypothesis that OP-tyrosine may serve as a biomarker of OP exposure in mice. A MALDI-TOF mass spectrometry strategy to analyze diethoxyphosphate-tyrosine of . m/. z 318 was developed. The adduct was synthesized by incubating . l-tyrosine with chlorpyrifos oxon at pH 8.1. The adduct eluted from a reverse phase HPLC column with 22-23% acetonitrile. The fragmentation spectrum of the . m/. z 318 precursor ion confirmed its identity as diethoxyphosphate-tyrosine. Diethoxyphosphate-tyrosine was isolated from chlorpyrifos oxon treated mouse albumin after digesting the protein with pronase. Mice (. n=. 3 per group) were treated with a nontoxic dose of chlorpyrifos oxon (3. mg/kg) and a toxic dose (10. mg/kg transdermally). The pronase digested plasma yielded diethoxyphosphate-tyrosine up to 120. h after treatment with 3. mg/kg chlorpyrifos oxon and up to 144. h after 10. mg/kg. In contrast plasma AChE activity returned to normal after 24-72. h. In conclusion MALDI-TOF mass spectrometry can be used to diagnose exposure to chlorpyrifos oxon days after AChE inhibition assays are uninformative.

Original languageEnglish (US)
Pages (from-to)15-22
Number of pages8
JournalToxicology
Volume295
Issue number1-3
DOIs
StatePublished - May 16 2012

Fingerprint

Poisons
Mass spectrometry
Tyrosine
Blood Proteins
Mass Spectrometry
Blood
Acetylcholinesterase
Proteins
Pronase
Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry
Biomarkers
Serine
Catalytic Domain
Butyrylcholinesterase
Plasmas
O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphate
Albumins
Assays
High Pressure Liquid Chromatography
Ions

Keywords

  • Albumin
  • Biomarker
  • Chlorpyrifos oxon
  • MALDI mass spectrometry
  • Pronase
  • Tyrosine

ASJC Scopus subject areas

  • Toxicology

Cite this

@article{5d5140de23f1459c8d80cffedd988168,
title = "Mice treated with a nontoxic dose of chlorpyrifos oxon have diethoxyphosphotyrosine labeled proteins in blood up to 4 days post exposure, detected by mass spectrometry",
abstract = "Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity is an established biomarker of exposure to organophosphorus poisons (OP). Inhibition of activity is due to covalent binding of the OP to the active site serine. Mass spectrometry has made it possible to monitor OP exposure by analyzing OP adducts on tyrosine in proteins that have no active site serine. Our goal was to test the hypothesis that OP-tyrosine may serve as a biomarker of OP exposure in mice. A MALDI-TOF mass spectrometry strategy to analyze diethoxyphosphate-tyrosine of . m/. z 318 was developed. The adduct was synthesized by incubating . l-tyrosine with chlorpyrifos oxon at pH 8.1. The adduct eluted from a reverse phase HPLC column with 22-23{\%} acetonitrile. The fragmentation spectrum of the . m/. z 318 precursor ion confirmed its identity as diethoxyphosphate-tyrosine. Diethoxyphosphate-tyrosine was isolated from chlorpyrifos oxon treated mouse albumin after digesting the protein with pronase. Mice (. n=. 3 per group) were treated with a nontoxic dose of chlorpyrifos oxon (3. mg/kg) and a toxic dose (10. mg/kg transdermally). The pronase digested plasma yielded diethoxyphosphate-tyrosine up to 120. h after treatment with 3. mg/kg chlorpyrifos oxon and up to 144. h after 10. mg/kg. In contrast plasma AChE activity returned to normal after 24-72. h. In conclusion MALDI-TOF mass spectrometry can be used to diagnose exposure to chlorpyrifos oxon days after AChE inhibition assays are uninformative.",
keywords = "Albumin, Biomarker, Chlorpyrifos oxon, MALDI mass spectrometry, Pronase, Tyrosine",
author = "Wei Jiang and Duysen, {Ellen G.} and Oksana Lockridge",
year = "2012",
month = "5",
day = "16",
doi = "10.1016/j.tox.2012.03.001",
language = "English (US)",
volume = "295",
pages = "15--22",
journal = "Toxicology",
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TY - JOUR

T1 - Mice treated with a nontoxic dose of chlorpyrifos oxon have diethoxyphosphotyrosine labeled proteins in blood up to 4 days post exposure, detected by mass spectrometry

AU - Jiang, Wei

AU - Duysen, Ellen G.

AU - Lockridge, Oksana

PY - 2012/5/16

Y1 - 2012/5/16

N2 - Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity is an established biomarker of exposure to organophosphorus poisons (OP). Inhibition of activity is due to covalent binding of the OP to the active site serine. Mass spectrometry has made it possible to monitor OP exposure by analyzing OP adducts on tyrosine in proteins that have no active site serine. Our goal was to test the hypothesis that OP-tyrosine may serve as a biomarker of OP exposure in mice. A MALDI-TOF mass spectrometry strategy to analyze diethoxyphosphate-tyrosine of . m/. z 318 was developed. The adduct was synthesized by incubating . l-tyrosine with chlorpyrifos oxon at pH 8.1. The adduct eluted from a reverse phase HPLC column with 22-23% acetonitrile. The fragmentation spectrum of the . m/. z 318 precursor ion confirmed its identity as diethoxyphosphate-tyrosine. Diethoxyphosphate-tyrosine was isolated from chlorpyrifos oxon treated mouse albumin after digesting the protein with pronase. Mice (. n=. 3 per group) were treated with a nontoxic dose of chlorpyrifos oxon (3. mg/kg) and a toxic dose (10. mg/kg transdermally). The pronase digested plasma yielded diethoxyphosphate-tyrosine up to 120. h after treatment with 3. mg/kg chlorpyrifos oxon and up to 144. h after 10. mg/kg. In contrast plasma AChE activity returned to normal after 24-72. h. In conclusion MALDI-TOF mass spectrometry can be used to diagnose exposure to chlorpyrifos oxon days after AChE inhibition assays are uninformative.

AB - Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity is an established biomarker of exposure to organophosphorus poisons (OP). Inhibition of activity is due to covalent binding of the OP to the active site serine. Mass spectrometry has made it possible to monitor OP exposure by analyzing OP adducts on tyrosine in proteins that have no active site serine. Our goal was to test the hypothesis that OP-tyrosine may serve as a biomarker of OP exposure in mice. A MALDI-TOF mass spectrometry strategy to analyze diethoxyphosphate-tyrosine of . m/. z 318 was developed. The adduct was synthesized by incubating . l-tyrosine with chlorpyrifos oxon at pH 8.1. The adduct eluted from a reverse phase HPLC column with 22-23% acetonitrile. The fragmentation spectrum of the . m/. z 318 precursor ion confirmed its identity as diethoxyphosphate-tyrosine. Diethoxyphosphate-tyrosine was isolated from chlorpyrifos oxon treated mouse albumin after digesting the protein with pronase. Mice (. n=. 3 per group) were treated with a nontoxic dose of chlorpyrifos oxon (3. mg/kg) and a toxic dose (10. mg/kg transdermally). The pronase digested plasma yielded diethoxyphosphate-tyrosine up to 120. h after treatment with 3. mg/kg chlorpyrifos oxon and up to 144. h after 10. mg/kg. In contrast plasma AChE activity returned to normal after 24-72. h. In conclusion MALDI-TOF mass spectrometry can be used to diagnose exposure to chlorpyrifos oxon days after AChE inhibition assays are uninformative.

KW - Albumin

KW - Biomarker

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KW - MALDI mass spectrometry

KW - Pronase

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VL - 295

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JO - Toxicology

JF - Toxicology

SN - 0300-483X

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