Acetylthiocholine iodide

S-Acetylthiocholine iodide [1866-15-5] M 289.2, m 203-204°, 204°, 204-205°. Recrystd from propan-l-ol (or wo-PrOH, or EtOH/Et20) until almost colourless and dried in a vacuum desiccator over P2O5. Solubility in H2O is 1% w/v. A 0.075M (21.7mg/mL) solution in O.IM phosphate buffer pH 8.0 is stable for 10-15 days if kept refrigerated. Store away from light. It is available as a 1% soln in H2O. [Biochemical Pharmacology 7, 88 I96I IR Hansen Acta Chem Scand 13 151 1959, 11 537 1957 Clin Chim Acta 2 316 7957 Zh Obshch Khim 22 267 1952.]... 

Reagents Acetylthiocholine iodide or chloride (ATCh, Sigma) maleate buffer 0.1 M, pH = 6.0 sodium citrate CuS04-5H20 distilled H20 potassium ferricyanide commercial acetylcholinesterase or water extract any cholinesterase-containing animal or plant. 

Chemiluminescent probes based on the dioxetane moiety are now being developed for the detection of cholinesterase activity <2002JA4874>. In this particular case, the nucleophilic thiol generated from hydrolysis of acetylthiocholine iodide triggers the formation of the thiolate 61 and by-product 62 through nucleophilic attack on the disulfide bond of 60 (Scheme 14). 

Table 1. The effect of 1 mM NaF + 20 pM A1C13 on the acetylcholinesterase activity (AChE) in freshly prepared intact RBC and in hemolysate of patients with AD (mean age 72.5 5.1 years), age-matched healthy controls (AM-HS) (72.1 1.6 years), and the group of young healthy subjects (YS) (35.9 8.5 years). Whole venous blood samples were drawn from each subject after overnight fasting., always at 07 30 AM. Red blood cells (RBC) were isolated from the blood of patients with AD, AM-HS, and YS by centrifugation [68], RBC AChE activity was evaluated in intact freshly prepared RBC or hemolyzate following the spectrophotometric method [45] with modifications. Buffer was Tris-HCl, pH 7.5 in the solution of 154 mmol L 1 NaCl, acetylthiocholine iodide was a substrate. Measurement of enzymatic activity was performed in fluorimeter polystyrene cuvettes for 3 min (UV/VIS spectrophotometer Shimadzu, Japan). The effects of 1 mmol L-1 NaF in the presence of 20 pmol L 1 A1C13 were measured. Data are expressed in percentage of the AChE activity in the absence of aluminum and fluoride ions. No differences between the AChE activity were found between the investigated groups...

Koitka, M. et al. Determination of rat serum esterase activities by an HPLC method using s-acetylthiocholine iodide and p-nitrophenyl acetate. Anal. Biochem. 2008, 381, 113-122. 

Organophosphorus compounds—inhibition of cholinesterase. To each of two tubes add 3 ml of dithiobisnitrobenzoic acid solution, 0.1 ml of 5% acetylthiocholine iodide solution, and 20 ml of normal serum to the first tube add 0.2 ml of water and to the second tube add 0.2 ml of the filtered sample and allow to stand for 2 minutes. Any significant difference in colour between the tubes is suggestive of the presence of an organophosphorus compound or other cholinesterase inhibitor. 

Acetylthiocholine iodide concentration for maximum RBC-AChE activity. 

The substrates used were acetylthiocholine iodide andbutyrylthiocholiae iodide for AChE and BuChE activity, respectively... 

Acetylthiocholine Iodide, Another automated procedure for cholinesterase inhibition studies has been used by Levine et al. (18) and by Voss (19). The method uses acetylthiocholine iodide as substrate and dithiobisnitrobenzoic acid (DTNB). Cholinesterase sphts the substrate, and the thiocholine released reduces the DTNB to the yellow anion of thionitrobenzoic acid, whose absorbance is measured at 420 fi,... 

In this section, we discuss about the screen printed electrode (SPE) based AChE sensors for the selective determination of OP and CA pesticides. In the past decades, several attempts were made by the researchers to develop SPE based pesticide sensors, where the enzyme AChE was immobilized either directly onto the electrode or above other matrices incorporated SPE surfaces. Both approaches resulted in the good, rapid detection of OP and CA pesticides. Earlier, Hart et al. employed AChE/SPE to detect OP and CA pesticides [21], They measured the enzyme activity from the rate of hydrolysis of acetylthiocholine iodide. Three polymers such as hydroxyethyl cellulose, dimethylaminoethyl methacrylate, and polyethyleneimine were used as enzyme immobilization matrices. Initially, electrodes were exposed to drops of water or pesticide solution, dried and their activity was screened after 24 h. They found that, when the enzyme matrix was hydroxyethyl cellulose, electrode activity inhibited both by water as well as by pesticides. While with co-polymer matrix, a significant response towards pesticides alone was observed. Further, the long-term storage stability of electrodes was highest when the enzyme matrix consisted of the co-polymer. The electrodes retained their activity for nearly one year. In contrast, the electrodes made of hydroxyethyl cellulose or polyethyleneimine possess less stability. 

The method for the demonstration of AChE followed the procedures of Koelle and Friedenwald (1949) and Lewis (1961). Slides were incubated for 15 h in 100 mL of stock solution (see below) to which had been added 116 mg of S-acetylthiocholine iodide and 3.0 mg ethopropazine (May Baker). The slides were rinsed with tap water and developed for 10 min in 1% sodium sulphide (1.0 g in 100 mL of water) at pH 7.5. They were then rinsed with water and immersed in 4% paraformaldehyde in phosphate buffer for... 

Acetylcholinesterase (AChE) The lyophilized enzyme from electric eel (Sigma) was dissolved in 0.05M phosphate buffer (pH-7.4) at a concentration of 20 pg/mL. Acetylthiocholine iodide was used as substrate at a final concentration of 5x10 4M in buffer. 5,5 -Dithiobis-(2-nitrobenzoic acid) (DTNB) at a final concentration of 3.8xlO 2M was used to monitor the released thiocholine according to a published procedure (41) with slight modification. Acetone was used as a solvent for the inhibitors. 

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