This article describes acetylcholinesterase (AChE), an enzyme involved in parasympathetic neurotransmission, its activity, and how its inhibition can be pharmacologically useful for treating dementia, caused by Alzheimer's disease, or as a warfare method due to the action of nerve agents. The chemical concepts related to the irreversible inhibition of AChE, its reactivation, and aging are discussed, along with a relationship to the current international legislation on chemical weapons.

• Keywords
• Alzheimer’s disease, Chemical Weapons Convention, acetylcholinesterase, nerve agents,
• MeSH
• Acetylcholinesterase * metabolism   MeSH
• Alzheimer Disease * drug therapy   enzymology   MeSH
• Chemical Warfare legislation & jurisprudence   MeSH
• Cholinesterase Inhibitors therapeutic use   MeSH
• GPI-Linked Proteins antagonists & inhibitors   metabolism   MeSH
• Humans MeSH
• Nerve Agents * MeSH
• Aging metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Acetylcholinesterase * MeSH
• ACHE protein, human MeSH Browser
• Cholinesterase Inhibitors MeSH
• GPI-Linked Proteins MeSH
• Nerve Agents * MeSH

Lipases are enzymes responsible for the conversion of triglycerides and other esterified substrates, they are involved in the basic metabolism of a wide number of organisms, from a simple microorganism and to mammals. They also have broad applicability in many fields from which industrial biotechnology, the production of cleaning agents, and pharmacy are the most important. The use of lipases in analytical chemistry where it can serve as a part of biosensors or bioassays is an application of growing interest and has become another important use. This review is focused on the description of lipases chemistry, their current applications and the methods for their assay measurement. Examples of bioassays and biosensors, including their physical and chemical principles, performance for specific substrates, and discussion of their relevance, are given in this work.

• Keywords
• amperometry, bioassay, biorecognition, biosensor, catalysis, enzyme, ester, lipase, nanoparticle, nanostructure, potentiometry, voltammetry,
• MeSH
• Enzyme Activation MeSH
• Biosensing Techniques methods   standards   MeSH
• Biological Assay methods   standards   MeSH
• Electrochemical Techniques MeSH
• Hydrolysis MeSH
• Catalysis MeSH
• Lipase chemistry   metabolism   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Lipase MeSH

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are two enzymes sensitive to various chemical compounds having ability to bind to crucial parts of these enzymes. Boldine is a natural alkaloid and it was mentioned in some older works that it can inhibit some kinds of AChE. We reinvestigated this effect on AChE and also on BChE using acetyl (butyryl) thiocholine and Ellman's reagents as standard substances for spectrophotometric assay. We found out IC50 of AChE equal to 372 μmol/l and a similar level to BChE, 321 μmol/l. We conclude our experiment by a finding that boldine is cholinesterase inhibitor; however we report significantly weaker inhibition than that suggested in literature. Likewise, we tried to investigate the mechanism of inhibition and completed it with in silico study. Potential toxic effect on cholinesterases in real conditions is also discussed.

• MeSH
• Acetylcholinesterase metabolism   MeSH
• Aporphines chemistry   pharmacology   MeSH
• Butyrylcholinesterase chemistry   metabolism   MeSH
• Cholinesterase Inhibitors chemistry   pharmacology   MeSH
• HEK293 Cells MeSH
• Humans MeSH
• Models, Molecular MeSH
• Secondary Metabolism * MeSH
• Substrate Specificity drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Acetylcholinesterase MeSH
• Aporphines MeSH
• boldine MeSH Browser
• Butyrylcholinesterase MeSH
• Cholinesterase Inhibitors MeSH

Biperiden is a drug used in Parkinson disease treatment and it serves also as an antiseizures compound in organophosphates poisoning. It acts as antagonist of muscarinic receptor activated by acetylcholine while the enzyme acetylcholinesterase (AChE) cleaves acetylcholine in synaptic junction into choline and acetic acid. This enzyme is inhibited by various compounds; however there has not been proposed evidence about interaction with biperiden molecule. We investigated this interaction using standard Ellman's assay and experimental findings were critically completed with an in silico prediction by SwissDock docking software. Uncompetitive mechanism of action was revealed from Dixon plot and inhibition constant (Ki ) was calculated to be 1.11 mmol/l. The lowest predicted binding energy was -7.84 kcal/mol corresponding to H-bond between biperiden molecule and Tyr 341 residuum in protein structure of AChE. This interaction seems to be further stabilized by π-π interaction with Tyr 72, Trp 286, and Tyr 341. In conclusion, biperiden appears as a very weak inhibitor but it can serve as a lead structure in a pharmacological research.

• MeSH
• Acetylcholinesterase metabolism   MeSH
• Biperiden chemistry   pharmacology   therapeutic use   MeSH
• Cholinesterase Inhibitors chemistry   pharmacology   therapeutic use   MeSH
• Enzyme Assays MeSH
• Humans MeSH
• Models, Molecular MeSH
• Parkinson Disease drug therapy   enzymology   MeSH
• Substrate Specificity drug effects   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Acetylcholinesterase MeSH
• Biperiden MeSH
• Cholinesterase Inhibitors MeSH

Smartphones are popular devices frequently equipped with sensitive sensors and great computational ability. Despite the widespread availability of smartphones, practical uses in analytical chemistry are limited, though some papers have proposed promising applications. In the present paper, a smartphone is used as a tool for the determination of cholinesterasemia i.e., the determination of a biochemical marker butyrylcholinesterase (BChE). The work should demonstrate suitability of a smartphone-integrated camera for analytical purposes. Paper strips soaked with indoxylacetate were used for the determination of BChE activity, while the standard Ellman's assay was used as a reference measurement. In the smartphone-based assay, BChE converted indoxylacetate to indigo blue and coloration was photographed using the phone's integrated camera. A RGB color model was analyzed and color values for the individual color channels were determined. The assay was verified using plasma samples and samples containing pure BChE, and validated using Ellmans's assay. The smartphone assay was proved to be reliable and applicable for routine diagnoses where BChE serves as a marker (liver function tests; some poisonings, etc.). It can be concluded that the assay is expected to be of practical applicability because of the results' relevance.

• Keywords
• CMYK, RGB, acetylcholinesterase, butyrylcholinesterase, colorimetry, diagnosis, digital photography, imagination, mobile phone, naked eye detection, photography, photometry,
• MeSH
• Butyrylcholinesterase metabolism   MeSH
• Butyrylthiocholine analysis   metabolism   MeSH
• Smartphone * MeSH
• Enzyme Assays instrumentation   methods   MeSH
• Photography instrumentation   MeSH
• Colorimetry instrumentation   MeSH
• Limit of Detection MeSH
• Mobile Applications MeSH
• Mice, Inbred BALB C MeSH
• Mice MeSH
• Reproducibility of Results MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Butyrylcholinesterase MeSH
• Butyrylthiocholine MeSH

Different toxic compounds can target the cholinergic nervous system. Acetylcholinesterase (AChE; EC 3.1.1.7) is one of the most crucial components of the cholinergic nervous system and thus many of the toxins interact with this enzyme. As to inhibitors, nerve agents used as chemical warfare, some insecticides, and drugs influencing the cholinergic system are common examples of AChE inhibitors. Once inhibited by a neurotoxic compound, a serious cholinergic crisis can occur. On the other hand, sensitivity of AChE to the inhibition can be used for analytical purposes. In this study, a simple disposable biosensor with AChE as a recognition element was devised. AChE was immobilized onto a cellulose matrix and indoxylacetate was used as a chromogenic substrate. The enzyme reaction was assessed by the naked eye using arbitrary units and pyridostigmine, tacrine, paraoxon, carbofuran, soman and VX were assayed as selected inhibitors. A good stability of the biosensors was found, with no aging over a quarter of a year and minimal sensitivity to the interference of organic solvents. The limit of detection ranged from 10 to 100 nmol/L for the compounds tested with a sample volume of 40 µL.

• Keywords
• Ellman′s method, acetylcholinesterase, carbofuran, indoxylacetate, inhibitor, pesticide, rivastigmine, sarin,
• Publication type
• Journal Article MeSH

Cholinesterases are enzymes able to hydrolyze the neurotransmitter acetylcholine and thus to terminate transmission. Once the enzymes are inhibited, excitotoxicity can appear in the adjacent cells. It is well known that oxidative stress is involved in the toxicity of cholinesterase inhibitors. Commonly, stress follows inhibition of cholinesterases and disappears shortly afterwards. In the present experiment, it was decided to test the impact of an inhibitor, neostigmine, on oxidative stress in BALB/c mice after a longer interval. The animals were sacrificed three days after onset of the experiment and spleens and livers were collected. Reduced glutathione (GSH), glutathione reductase (GR), glutathione S-transferase (GST), thiobarbituric acid reactive substances (TBARS), ferric reducing antioxidant power (FRAP), caspase-3 and activity of acetylcholinesterase (AChE) were assayed. The tested markers were not altered with exceptions of FRAP. The FRAP values indicate accumulation of low molecular weight antioxidants in the examined organs. The role of low molecular weight antioxidants in the toxicity of AChE inhibitors is discussed.

• Keywords
• acetylcholinesterase, antioxidant, butyrylcholinesterase, excitotoxicity, glutathione, inhibitor, neostigmine, oxidative stress,
• Publication type
• Journal Article MeSH

Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer's disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a "cholinergic anti-inflammatory pathway" which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system.

• MeSH
• Acetylcholinesterase immunology   MeSH
• Butyrylcholinesterase immunology   MeSH
• Cholinesterase Inhibitors chemistry   immunology   MeSH
• Immunity drug effects   MeSH
• Immune System drug effects   MeSH
• Humans MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Acetylcholinesterase MeSH
• Butyrylcholinesterase MeSH
• Cholinesterase Inhibitors MeSH

The enzyme acetylcholinesterase (AChE) is an important part of cholinergic nervous system, where it stops neurotransmission by hydrolysis of the neurotransmitter acetylcholine. It is sensitive to inhibition by organophosphate and carbamate insecticides, some Alzheimer disease drugs, secondary metabolites such as aflatoxins and nerve agents used in chemical warfare. When immobilized on a sensor (physico-chemical transducer), it can be used for assay of these inhibitors. In the experiments described herein, an AChE- based electrochemical biosensor using screen printed electrode systems was prepared. The biosensor was used for assay of nerve agents such as sarin, soman, tabun and VX. The limits of detection achieved in a measuring protocol lasting ten minutes were 7.41 × 10(-12) mol/L for sarin, 6.31 × 10(-12) mol /L for soman, 6.17 × 10(-11) mol/L for tabun, and 2.19 × 10(-11) mol/L for VX, respectively. The assay was reliable, with minor interferences caused by the organic solvents ethanol, methanol, isopropanol and acetonitrile. Isopropanol was chosen as suitable medium for processing lipophilic samples.

• MeSH
• Acetylcholinesterase chemistry   MeSH
• Equipment Failure Analysis MeSH
• Biosensing Techniques instrumentation   MeSH
• Chemical Warfare Agents analysis   chemistry   MeSH
• Cholinesterase Inhibitors analysis   chemistry   MeSH
• Equipment Design MeSH
• Conductometry instrumentation   MeSH
• Neurotoxins analysis   chemistry   MeSH
• Reproducibility of Results MeSH
• Sensitivity and Specificity MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Acetylcholinesterase MeSH
• Chemical Warfare Agents MeSH
• Cholinesterase Inhibitors MeSH
• Neurotoxins MeSH

Caffeine is an alkaloid with a stimulant effect in the body. It can interfere in transmissions based on acetylcholine, epinephrine, norepinephrine, serotonin, dopamine and glutamate. Clinical studies indicate that it can be involved in the slowing of Alzheimer disease pathology and some other effects. The effects are not well understood. In the present work, we focused on the question whether caffeine can inhibit acetylcholinesterase (AChE) and/or, butyrylcholinesterase (BChE), the two enzymes participating in cholinergic neurotransmission. A standard Ellman test with human AChE and BChE was done for altering concentrations of caffeine. The test was supported by an in silico examination as well. Donepezil and tacrine were used as standards. In compliance with Dixon's plot, caffeine was proved to be a non-competitive inhibitor of AChE and BChE. However, inhibition of BChE was quite weak, as the inhibition constant, Ki, was 13.9 ± 7.4 mol/L. Inhibition of AChE was more relevant, as Ki was found to be 175 ± 9 µmol/L. The predicted free energy of binding was -6.7 kcal/mol. The proposed binding orientation of caffeine can interact with Trp86, and it can be stabilize by Tyr337 in comparison to the smaller Ala328 in the case of human BChE; thus, it can explain the lower binding affinity of caffeine for BChE with reference to AChE. The biological relevance of the findings is discussed.

• MeSH
• Acetylcholinesterase metabolism   MeSH
• Butyrylcholinesterase metabolism   MeSH
• Cholinesterase Inhibitors pharmacology   MeSH
• Caffeine pharmacology   MeSH
• Humans MeSH
• Models, Molecular MeSH
• Computer Simulation MeSH
• Recombinant Proteins metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Acetylcholinesterase MeSH
• Butyrylcholinesterase MeSH
• Cholinesterase Inhibitors MeSH
• Caffeine MeSH
• Recombinant Proteins MeSH