Йодид ацетилтиохолина

Description

Acetylthiocholine iodide is a quaternary ammonium salt, a thioanalogue of acetylcholine with iodide as a counterion, a standard substrate for determining the activity of cholinesterases. Formula C7H16NOS,I, CAS 1866-15-5, EC number 217-474-1, NSC number 44139, HS code 293090909090. Molecular weight 289.178, exact mass 289.00000. PSA specs: 42.37. Synonyms: S-acetylthiocholine iodide, acetylthiocholine diiodide, [2-(acetylthio)ethyl]trimethylammonium iodide.

Physico-chemical characteristics

• Melting point: 203-204 °C
• Solubility in water: 100 mg/ml
• Storage conditions: 2-8 °C

Substance class and purpose

Acetylthiocholine iodide is a synthetic analogue of the natural neurotransmitter acetylcholine, in which the oxygen atom of the ester bond is replaced by a sulfur atom. The replacement makes the hydrolysis product (thiocholine) convenient for colorimetric detection.

Mechanism of action and application

The main application is as a substrate in the Ellman method for determining the activity of acetylcholinesterase and butyrylcholinesterase. The enzyme hydrolyzes acetylthiocholine to form thiocholine, which reduces the chromogenic reagent DTNB (5,5'-dithiobis-2-nitrobenzoic acid, Ellman's reagent), yielding the yellow anion 2-nitro-5-thiobenzoic acid with an absorption maximum of about 412 nm (according to other sources 405 nm). The typical composition of the Ellman method reaction mixture is 0.5 mM acetylthiocholine iodide and 1 mM DTNB in ​​50 mM sodium phosphate buffer at pH 8.0. The method remains the main biochemical method for diagnosing the activity of cholinesterases, including for assessing the degree of poisoning with organophosphorus compounds and neurotoxins.

Biosensors for the determination of pesticides

In addition to the Ellman colorimetric method, acetylthiocholine iodide is used as a substrate in amperometric acetylcholinesterase-based biosensors for the field determination of organophosphate pesticides. In such sensors, the anodic current of thiocholine oxidation, formed during enzymatic hydrolysis of the substrate, is recorded; the current is inversely proportional to the concentration of pesticide inhibitor in the sample, since organophosphorus compounds inhibit the activity of the immobilized enzyme. Biosensor designs based on platinum-iridium electrodes, conducting polymers and nanocomposites (for example, Ag-rGO-NH2) achieve detection limits at the level of tenths - units of micromoles per liter for dichlorvos, parathion and other organophosphorus poisons.

Safety Information

• Packing level: III
• Hazard category: 6.1
• Transport codes: UN 2811, class 6
• WGK Germany: 3
• Hazard class code: R21
• Safety instructions: 26-36
• RTECS number: FZ9865000
• Tags: T
• Precautions: P261, P280, P301+P310, P305+P351+P338, P312
• Hazard statements: H301, H311, H315, H319, H335
• GHS classification: hazardous, H301 (100%) - toxic if swallowed, acute oral toxicity. Aggregated list of precautionary measures according to the GHS classification: P261, P264, P270, P271, P280, P301+P310, P302+P352, P304+P340, P305+P351+P338, P312, P321, P322, P330, P332+P313, P337+P313, P361, P362, P363, P403+P233, P405, P501. Information provided by 47 companies from 5 notifications for the C&L ECHA inventory

Storage conditions

Store at 2-8 °C, in a tightly closed container, away from heat sources. Transport according to UN 2811, packaging level III, hazard category 6.1.