Comparison of Efficiency of Purification (from Human Plasma) of a Nerve Agent Adduct of Butyrylcholinesterase Between the Affinity Gel Method and Immunomagnetic Separation

From Crude Extracts to Purity: A Comparative Study of Butyrylcholinesterase Purification

Butyrylcholinesterase (BChE; EC 3.1.1.8) is an enzyme found in blood plasma and various tissues, playing a key role in metabolizing esters and detoxifying various substances. In this study, we developed a modified purification protocol for BChE from human serum, achieving a higher purification yield (38.3%) and specific activity (60,500 U/mg) compared to previous reports. The method employed a single round of acid dialysis, Sephadex G50 gel filtration chromatography, and procainamide Sepharose 4 fast flow affinity chromatography. Our new approach excludes the commonly used DEAE Trisacryl M chromatography. The goal was to compare this method with our previously employed purification protocols. This study demonstrates that optimizing chromatography steps can enhance enzyme recovery and activity, though further refinement may be needed for higher purification folds. This improved methodology offers a valuable approach for efficient BChE purification with potential for broader applications.

Mass spectrometry detection of organophosphorus pesticide adducts on butyrylcholinesterase and albumin

This study established a method to prepare and detect OPs adducts on butyrylcholinesterase (BChE) and human serum albumin (HSA). OPs (methyl paraoxon, ethyl paraoxon, methyl parathion, parathion) were incubated with BChE or HSA in vitro, and the adducts of OPs-BChE or OPs-HSA were prepared and qualitatively analyzed by ultra-performance liquid chromatography data-dependent high-resolution tandem mass spectrometry (UPLC-ddHRMS/MS). The amounts of BChE and HSA in the incubating systems were varied and the resulting amounts of the adducts were determined using linear regression. OPs-BChE in the blood were isolated by immunomagnetic separation (IMS), and then digested into the OPs-nonapeptide adduct by pepsin. The proteins in the remaining blood plasma were precipitated and digested by pronase to OPs-tyrosines(OPs-Tyr), which were quantified by UPLC-ddHRMS/MS. 4 OPs-nonapeptides and 4 OPs-Tyr adducts were obtained through the process above. The relative mass deviation of incubated adducts between the actual and theoretical exact masses was less than 10 ppm, and further confirmed by fragmentation mass spectra analysis. Calibration curves were linear for all adducts with a coefficient of determination value (R2) ≥0.995. The limits of detection (LOD) and limits of quantification (LOQ) for adducts detected by MS ranged from 0.05 to 1.0 ng/mL, and from 0.1 to 2.0 ng/mL, respectively. The recovery percentages for adducts ranged from 76.1 % to 107.1 %, matrix effects ranged from 83.4 % to 102.1 %. The inter-day and intra-day precision were 6.1-10.1 % and 6.9-12.9 % for adducts. This study provides a new reference method for the detection of organophosphorus pesticide poisoning. In addition, two blood samples with organophosphorus poisoning were tested by the designed method, and the corresponding adducts were detected in both samples.