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InChI:InChI=1/C5H13NS/c1-5(7)6(2,3)4/h5H,1-4H3/p+1

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• 6050-81-3 S-acetylthiocholine chloride 
• 4468-05-7 acetylthiocholine 
• 1866-15-5 acetylthiocholine iodide 

Relevant academic research and scientific papers

Colorimetric and fluorometric assays for acetylcholinesterase and its inhibitors screening based on a fluorescein derivate

A fluorescein-based sensor was developed for the AChE activity assay and the inhibitor screening. The sensor provided the dual assay methods for the screening of AChE activity in the presence or absence of inhibitor. The colorimetric and fluorometric assa

Phenylsulfonic acid functionalized carbon quantum dots based biosensor for acetylcholinesterase activity monitoring and inhibitor screening

Phenylsulfonic acid functionalized carbon quantum dots (PSA-CQDs) were prepared and used to construct a convenient and reliable fluorometric biosensor for acetylcholinesterase (AChE) activity and inhibitor screening. Effective static quenching process occurred owing to the formation of nonfluorescent complex when copper(ii) ions were added to PSA-CQDs, which results in its fluorescence quenching due to strong coordination of copper ions to sulfonic groups of PSA-CQDs. As a result, the fluorometric assay for AChE was established based on the stronger affinity between copper and thiocholine hydrolyzed from acetylthiocholine under the hydrolysis of AChE which can induce fluorescence recovery. Meanwhile, the inhibition effect of tacrine to AChE was assessed because its effective inhibition effect to AChE leads to the prevention of hydrolysis of acetylthiocholine and the following occurrence of PET process which causes the quenching of fluorescence. This detection method is convenient and efficient, which has high sensitivity with detection limit as low as 2.6 U L-1 and a broad linear scope ranging from 3.8 to 80.0 U L-1. This work proposed a competitive assay strategy among the sulfonic acid modified probe, copper cation and thiocholine to quantify AChE activity using functional carbon quantum dots, and can be utilized to design detection methods for other thiol-containing targets of interest.

Direct mass spectrometry analysis of biofluid samples using slug-flow microextraction nano-electrospray ionization

Direct mass spectrometry (MS) analysis of biofluids with simple procedures represents a key step in the translation of MS techniques to clinical and point-of-care applications. The current study reports the development of a single-step method using slug-flow microextraction and nano-electrospray ionization for MS analysis of organic compounds in blood and urine. High sensitivity and quantitation precision have been achieved in the analysis of therapeutic and illicit drugs in 5 μL samples. Real-time chemical derivatization has been incorporated for analyzing anabolic steroids. The monitoring of enzymatic functions has also been demonstrated with cholinesterase in wet blood. The reported study encourages the future development of disposable cartridges, which function with simple operation to replace the traditional complex laboratory procedures for MS analysis of biological samples.

Electropolymerization-Induced Positively Charged Phenothiazine Polymer Photoelectrode for Highly Sensitive Photoelectrochemical Biosensing

Exploring the fabrication of an electrode with high photoelectric conversion efficiency and abundant functional groups for ideal photoelectrochemical (PEC) sensor development is highly urgent but faces a significant challenge. Herein we report an electropolymerization strategy for the preparation of phenothiazine polymeric film on an indium tin oxide (ITO) surface (PPT/ITO), within only a few seconds, and monomers. The fabricated PPT/ITO electrode possessed excellent stability and abundant quaternary ammonium salt groups for developing a highly sensitive PEC sensor through electrostatic binding with negatively charged materials. In this context, a CdS QDs-functionalized PPT/ITO electrode (CdS/PPT/ITO) was proposed and applied to the analysis of chlorpyrifos, used as a model target organophosphorous pesticide (OP). The thiocholine generated from acetylcholinesterase (AChE)-induced catalyzed hydrolysis of acetylthiocholine (ATCh) efficiently directed CdS QDs away from PPT/ITO via electrostatic repulsion, subsequently decreasing PEC current, whereas chlorpyrifos prohibited the generation of thiocholine through inhibiting AChE activity. As compared to the case where chlorpyrifos is absent, significantly enhanced PEC current is determined and is proportional to chlorpyrifos amounts. Thus, the developed CdS/PPT/ITO-based PEC sensor achieved excellent chlorpyrifos biosensing with improved sensitivity down to approximately ng/mL level with good specificity. We envision the proposed strategy will provide a new path to conveniently fabricate photoelectrodes possessing high performance, which will have more useful applications in PEC sensing.

Resurfaced fluorescent protein as a sensing platform for label-free detection of copper(II) ion and acetylcholinesterase activity

Protein engineering by resurfacing is an efficient approach to provide new molecular toolkits for biotechnology and bioanalytical chemistry. H39GFP is a new variant of green fluorescent protein (GFP) containing 39 histidine residues in the primary sequence that was developed by protein resurfacing. Herein, taking H39GFP as the signal reporter, a label-free fluorometric sensor for Cu2+ sensing was developed based on the unique multivalent metal ion-binding property of H39GFP and fluorescence quenching effect of Cu2+ by electron transfer. The high affinity of H39GFP with Cu2+ (Kd, 16.2 nM) leads to rapid detection of Cu2+ in 5 min with a low detection limit (50 nM). Using acetylthiocholine (ATCh) as the substrate, this H39GFP/Cu2+ complex-based sensor was further applied for the turn-on fluorescence detection of acetylcholinesterase (AChE) activity. The assay was based on the reaction between Cu2+ and thiocholine, the hydrolysis product of ATCh by AChE. The proposed sensor is highly sensitive (limit of detection (LOD) = 0.015 mU mL-1) and is feasible for screening inhibitors of AChE. Furthermore, the practicability of this method was demonstrated by the detection of pesticide residue (carbaryl) in real food samples. Hence, the successful applications of H39GFP in the detection of metal ion and enzyme activity present the prospect of resurfaced proteins as versatile biosensing platforms.

Rapid detection of irreversible acetylcholineasterase inhibitor by mass spectrometry assay

Here we developed a rapid method to detect acetylcholinesterase (AChE) activity by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) for screening irreversible AChE inhibitors. Due to its good salt-tolerance and low sample consumption, MALDI-FTMS could facilitate rapid detection, especially detection in real application. AChE activity was determined through calculating abundance of substrate and product in mass spectrometry. By this approach, we investigated the relation of organophosphorous (OP) concentrations and AChE inhibition. Shown in different inhibition curves from different OP pesticides, enzyme inhibitions still kept good correlation with concentration of OPs. Finally, this AChE-inhibited method was applied to screen whole bloods of four decedents and discuss their death reason. In contrast to healthy persons, three of decedents showed low AChE activity, and probably died for irreversible AChE inhibitors. Through the following detecting in GC-MS/MS, the possible death reason of these three decedents was confirmed, and another decedent actually died for sumicidin, a non-AChE inhibitor. It demonstrated that screening irreversible AChE inhibitors by detecting enzyme activity in MALDI-FTMS provided fast and accurate analysis results and excluded another toxicants not functioning on AChE. This method offered alternative choices for indicating the existence of enzyme inhibitors.

Synthesis of Au(I) complex-based aqueous colloids for sensing of biothiols

The present work represents new facile route for synthesis of luminescent hydrophilic core-shell colloids, where the luminescence results from Au(I) complex (AuCl)2L with cyclic PNNP ligand (L). The synthesis is based on solvent mediated aggregation of (AuCl)2L in aqueous organic solutions. Instability of (AuCl)2L in aqueous organic solutions was minimized by specific hydrophilic shell deposition arisen from electrostatically driven adsorption of polyethylenimine onto (AuCl)2L-based cores. Luminescence of the colloids is stable for week at least due to restricted degradation of the luminescent complex at the interface and high positive exterior charge of the colloids. The sensing properties of the colloids towards thiols results from their complex formation with Au+ ions. The thiol-induced stripping of Au+ ions from the colloids quenches the luminescence. The optimal conditions for fluorescent recognition of cysteine, homocysteine and glutathione with lower detection limits about 1 μM are highlighted in the work.

off-On fluorescent sensing of organophosphate pesticides using a carbon dot-Au(III) complex

Herein, we report novel off-on fluorescent sensing of organophosphate pesticides using a carbon dot (CD)-Au(iii) complex/acetylcholinesterase (AChE) system. The above sensor utilizes the quenching of CD fluorescence by Au(iii) and its subsequent recovery by thiocholine, which is generated by AChE-catalyzed hydrolysis of acetylthiocholine (ATCh) and effectively scavenges Au(iii). In the presence of organophosphates, the catalytic activity of AChE is inhibited, allowing these species to be quantified based on the decreased recovery of CD fluorescence intensity. The developed sensor was used to analyze a real pesticide-spiked sample (4.48 μM), achieving a recovery of 99.85% and exhibiting a linear response range of 0.45-44.80 μM.

A mechanistic study of thioester hydrolysis with heavy atom kinetic isotope effects

The carbonyl-C, carbonyl-O, and leaving-S kinetic isotope effects (KIEs) were determined for the hydrolysis of formylthiocholine. Under acidic conditions, 13kobs = 1.0312, 18kobs = 0.997, and 34kobs = 0.995; for neutral conditions, 13kobs = 1.022, 18kobs = 1.010, and 34kobs = 0.996; and for alkaline conditions, 13kobs = 1.0263, 18kobs = 0.992, and 34kobs = 1.000. The observed KIEs provided helpful insights into a qualitative description of the bond orders in the transition state structure.

Novel enzymatic synthesis of core/shell AgNP/AuNC bimetallic nanostructure and its catalytic applications

Herein, we report the enzyme-mediated synthesis of bimetallic nanostructure consisting of gold nanoclusters shell- silver nanoparticles core (AuNCs-AgNPs) for catalytic reduction applications. For the synthesis of core AgNPs, thiocholine (TCh), an enzymatic product from the acetylcholinesterase (AChE), and acetylthiocholine (ATCh) interaction was used as a stabilizing agent. The AuNCs-AgNPs was prepared using TCh as a reducing as well as stabilizing agent. The synthesized AuNCs-AgNPs were characterized with help of UV–Vis spectroscopy, dynamic light scattering (DLS) analyses and High-Resolution Transmission Electron Microscopy (HR-TEM). The HR-TEM micrographs confirmed that the formation and arrangement of AuNCs on the core AgNPs, resulting in AuNCs-AgNP bimetallic structures. The catalytic reduction activity of thus prepared AgNPs and AuNCs-AgNPs was investigated against methyl orange (MO) and potassium ferricyanide K3[Fe(CN)6] in the presence of sodium borohydride (NaBH4). The rate constants (k), for MO and K3[Fe(CN)6] catalytic reduction in the presence of AuNCs -AgNPs were measured to be 2.3 × 10? 2 s? 1 and 1.219 × 10? 1 s? 1 respectively.