Proteomic analysis of adducted butyrylcholinesterase for biomonitoring organophosphorus exposures

Abstract

Organophosphorus (OP) compounds include a broad group of toxic chemicals such as insecticides, chemical warfare agents and antiwear agents. The liver cytochromes P450 bioactivate many OPs to potent inhibitors of serine hydrolases. Cholinesterases were the first OP targets discovered and are the most studied. They are used to monitor human exposures to OP compounds. However, the assay that is currently used has limitations. The mechanism of action of OP compounds is the inhibition of serine hydrolases by covalently modifying their active-site serine. After structural rearrangement, the complex OP inhibitor-enzyme is irreversible and will remain in circulation until the modified enzyme is degraded. Mass spectrometry is a sensitive technology for analyzing protein modifications, such as OP-adducted enzymes. These analyses also provide some information about the nature of the OP adduct. Our aim is to develop high-throughput protocols for monitoring OP exposures using mass spectrometry.

New insights on molecular interactions of organophosphorus pesticides with esterases

“…Peptide mass fingerprinting can be essential for human biological monitoring of OPs exposures due to the fact that OP-modified enzymes are more stable in the organism than intact OPs which are rapidly eliminated. (Marsillach et al, 2013a;2013b). Furthermore, tandem mass spectrometry (MS/MS) allows high-throughput identification of proteins in complex samples to be correlated with genomic information (Lin et al, 2003).…”

“…The LC-MS/MS analysis of OP exposures has shown to have several advantages over the currently used colorimetric enzyme activity assays: 1) the analysis does not require a separate blood draw for the determination of baseline activity levels; 2) it provides a more accurate measurement of the percentage modification of the active-site serine, and; 3) it also provides some information about the OP that adducted the active-site serine (e.g., a methyl-or ethyl based insecticide). The use of MS analysis for biomonitoring exposures to OP compounds improves the identification and characterization of biomarkers of exposure (Marsillach et al, 2013b).…”

Fabrication of Polymerized Crystalline Colloidal Array Thin Film Modified β-Cyclodextrin Polymer for Paraoxon-ethyl and Parathion-ethyl Detection

“…Figure 2A shows the optical images of the PCCA thin film fabricated using different concentrations of monomer. Different amounts of bis/acrylamide monomer solution (5,7,10,15,20,50, 100, and 150 μL from (a) to (h), respectively) were added to the same volume and concentration of polystyrene colloidal suspension with 50 μL of β-CD polymer solution (0.03 g/mL). All samples were fabricated at the same environmental temperature (25 C).…”

“…3,4 Most OP compounds and chemical nerve agents (CNAs) disrupt cholinesterase activity and lead to an inhibition of these enzymes resulting in cholinergic reactions that can have negative effects on the central nervous system, visual system, sensory capabilities, cognitive function, and could result in the death of humans or animals. 5,6 There is no need to emphasize the importance and urgency to develop a fast and effective method to detect these toxic agents in the environment and public places where the monitoring of individual exposure to CNAs have become increasingly important for national security and health protection purposes. While most OP compound analysis can be carried out using analytical techniques such as gas or liquid chromatography and mass spectrometry, these methods require high-cost instruments, extensive labor resources and lengthy time of operation.…”

Preparation and characterization of diethoxy- and monoethoxy phosphylated (‘aged’) serine haptens and use in the production of monoclonal antibodies

“…Indirectly, immunoprecipitation of OP-protein targets using antibodies to butyrylcholinesterase followed by digestion and mass spectral characterization of the OP-modified peptide has been applied to address the problem [20, 33-37]. …”