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Jimenez-Carretero M, Jabalera Y, Sola-Leyva A, Carrasco-Jimenez MP, Jimenez-Lopez C. Nanoassemblies of acetylcholinesterase and β-lactamase immobilized on magnetic nanoparticles as biosensors to detect pollutants in water. Talanta 2023; 258:124406. [PMID: 36870155 DOI: 10.1016/j.talanta.2023.124406] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/05/2023]
Abstract
The use of enzymes immobilized on magnetic nanoparticles to detect contaminants in aqueous samples has gained interest, since it allows the magnetic control, concentration and reuse of the enzymes. In this work, the detection of trace amounts of organophosphate pesticides (chlorpyrifos) and antibiotics (penicillin G) in water was attained by developing a nanoassembly formed by either inorganic or biomimetic magnetic nanoparticles used as substrates to immobilize acetylcholinesterase (AChE) and β-lactamase (BL). Other than the substrate, the optimization of the nanoassembly was done by testing enzyme immobilization both through electrostatic interaction (also reinforced with glutaraldehyde) and covalent bonds (by carbodiimide chemistry). Temperature (25 °C), ionic strength (150 mM NaCl) and pH (7) were set to ensure enzymatic stability and to allow both the nanoparticles and the enzymes to present ionic charges that would allow electrostatic interaction. Under these conditions, the enzyme load on the nanoparticles was ⁓0.1 mg enzyme per mg nanoparticles, and the preserved activity after immobilization was 50-60% of the specific activity of the free enzyme, being covalent bonding the one which yielded better results. Covalent nanoassemblies could detect trace concentrations of pollutants down to 1.43 nM chlorpyrifos and 0.28 nM penicillin G. They even permitted the quantification of 14.3 μM chlorpyrifos and 2.8 μM penicillin G. Also, immobilization conferred higher stability to AChE (⁓94% activity after 20 days storage at 4 °C) and allowed to reuse the BL up to 12 cycles.
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Affiliation(s)
| | - Ylenia Jabalera
- Department of Microbiology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
| | - Alberto Sola-Leyva
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Granada, 18071, Granada, Spain; Biosanitary Research Institute Ibs.GRANADA, 18014, Granada, Spain.
| | - Maria P Carrasco-Jimenez
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Granada, 18071, Granada, Spain.
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Toum Terrones Y, Laucirica G, Cayón VM, Fenoy GE, Cortez ML, Toimil-Molares ME, Trautmann C, Mamisollé WA, Azzaroni O. Highly sensitive acetylcholine biosensing via chemical amplification of enzymatic processes in nanochannels. Chem Commun (Camb) 2022; 58:10166-10169. [PMID: 35997520 DOI: 10.1039/d2cc02249d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acetylcholinesterase-modified nanochannels are proposed as reliable and reproducible nanofluidic sensors for highly sensitive detection of acetylcholine. The operation mechanism relies on the use of weak polyelectrolytes as "chemical amplifiers" that adjust/reconfigure the nanochannel surface charge in the presence of local pH changes induced by the enzymatic reaction. Experimental results show that the presence of acetylcholine can be transduced into measurable ionic signals with a low limit of detection.
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Affiliation(s)
- Yamili Toum Terrones
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET - CC 16 Suc. 4, 1900 La Plata, Argentina.
| | - Gregorio Laucirica
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET - CC 16 Suc. 4, 1900 La Plata, Argentina.
| | - Vanina M Cayón
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET - CC 16 Suc. 4, 1900 La Plata, Argentina. .,GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - Gonzalo E Fenoy
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET - CC 16 Suc. 4, 1900 La Plata, Argentina.
| | - M Lorena Cortez
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET - CC 16 Suc. 4, 1900 La Plata, Argentina.
| | | | - Christina Trautmann
- GSI Helmholtzzentrum für Schwerionenforschung, 64291 Darmstadt, Germany.,Technische Universität Darmstadt, Materialwissenschaft, 64287 Darmstadt, Germany
| | - Waldemar A Mamisollé
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET - CC 16 Suc. 4, 1900 La Plata, Argentina.
| | - Omar Azzaroni
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET - CC 16 Suc. 4, 1900 La Plata, Argentina.
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Regulation of Immune Functions by Non-Neuronal Acetylcholine (ACh) via Muscarinic and Nicotinic ACh Receptors. Int J Mol Sci 2021; 22:ijms22136818. [PMID: 34202925 PMCID: PMC8268711 DOI: 10.3390/ijms22136818] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 06/16/2021] [Accepted: 06/22/2021] [Indexed: 12/14/2022] Open
Abstract
Acetylcholine (ACh) is the classical neurotransmitter in the cholinergic nervous system. However, ACh is now known to regulate various immune cell functions. In fact, T cells, B cells, and macrophages all express components of the cholinergic system, including ACh, muscarinic, and nicotinic ACh receptors (mAChRs and nAChRs), choline acetyltransferase, acetylcholinesterase, and choline transporters. In this review, we will discuss the actions of ACh in the immune system. We will first briefly describe the mechanisms by which ACh is stored in and released from immune cells. We will then address Ca2+ signaling pathways activated via mAChRs and nAChRs on T cells and B cells, highlighting the importance of ACh for the function of T cells, B cells, and macrophages, as well as its impact on innate and acquired (cellular and humoral) immunity. Lastly, we will discuss the effects of two peptide ligands, secreted lymphocyte antigen-6/urokinase-type plasminogen activator receptor-related peptide-1 (SLURP-1) and hippocampal cholinergic neurostimulating peptide (HCNP), on cholinergic activity in T cells. Overall, we stress the fact that ACh does not function only as a neurotransmitter; it impacts immunity by exerting diverse effects on immune cells via mAChRs and nAChRs.
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Acetylcholine biosensor based on the electrochemical functionalization of graphene field-effect transistors. Biosens Bioelectron 2019; 148:111796. [PMID: 31665672 DOI: 10.1016/j.bios.2019.111796] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/17/2019] [Accepted: 10/17/2019] [Indexed: 01/30/2023]
Abstract
We present a new strategy of Acetylcholinesterease (AchE) immobilization on graphene field-effect transistors (gFETs) for building up Acetylcholine sensors. This method is based on the electrosynthesis of an amino moiety-bearing polymer layer on the graphene channel. The film of the copolymer poly(3-amino-benzylamine-co-aniline) (PABA) does not only provide the suitable electrostatic charge and non-denaturing environment for enzyme immobilization, but it also improves the pH sensitivity of the gFETs (from 40.8 to 56.3 μA/pH unit), probably due to its wider effective pKa distribution. The local pH changes caused by the enzyme-catalyzed hydrolysis produce a shift in the Dirac point of the gFETs to more negative values, which are evidenced as differences in the gFET conductivity and thereby constituted the signal transduction mechanism of the modified transistors. In this way, the constructed biosensors showed a LOD of 2.3 μM and were able to monitor Ach in the range from 5 to 1000 μM in a flow configuration. Moreover, they showed a sensitivity of -26.6 ± 0.7 μA/Ach decade and also exhibited a very low RSD of 2.6%, revealing good device-to-device reproducibility. The biosensors revealed an excellent selectivity to interferences known to be present in the extracellular milieu, and the response to Ach was recovered by 97.5% after the whole set of interferences injected. Finally, the biosensors showed a fast response time, with an average value of 130 s and a good long-term response.
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Cholinesterase confabs and cousins: approaching forty years. Chem Biol Interact 2013; 203:10-3. [PMID: 23085121 DOI: 10.1016/j.cbi.2012.10.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 10/04/2012] [Accepted: 10/09/2012] [Indexed: 11/23/2022]
Abstract
In the past four decades of cholinesterase (ChE) research, we have seen substantive evolution of the field from one centered around substrate and inhibitor kinetic profiles and compound characterizations to the analysis of ChE structure, first through the gene families and then by X-ray crystallographic determinations of the free enzymes and their complexes and conjugates. Indeed, these endeavors have been facilitated by recombinant DNA technologies, structure determinations and parallel studies in related proteins in the α/β-hydrolase fold family. This approach has not only contributed to a fundamental understanding of structure and function of a large family of hydrolase-like proteins possessing functions other than catalysis, but also has been used to develop new practical strategies for scavenging and antidotal activity in cases of organophosphate insecticide or nerve agent exposure.
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Anglade P, Larabi-Godinot Y. Historical landmarks in the histochemistry of the cholinergic synapse: Perspectives for future researches. ACTA ACUST UNITED AC 2010; 31:1-12. [PMID: 20203414 DOI: 10.2220/biomedres.31.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nearly one hundred years ago, acetylcholine (ACh) was proposed as a chemical agent responsible for nerve transmission at the synapse, the junction area between one neuron and its target cell. Since it has been proved that ACh played, indeed, a major role in the functioning of the nerve system in the vertebrates, cholinergic nerve transmission became a basic field of study in neuroscience. The birth of histochemistry and its ulterior developments allowed in situ localization of the molecular agents related to the functioning of the cholinergic synapse. This report presents historical landmarks in the histochemistry of major cholinergic agents (acetylcholinesterase, nicotinic acetylcholine receptor, choline acetyltransferase, and ACh), a domain which has greatly contributed to the knowledge of the nerve system. It is emphasized that despite extraordinary progresses made in this field, basic problems, such as in situ localization of ACh, still remain to be solved.
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Rosenberry TL. Acetylcholinesterase. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 43:103-218. [PMID: 891 DOI: 10.1002/9780470122884.ch3] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Bourne Y, Grassi J, Bougis PE, Marchot P. Conformational flexibility of the acetylcholinesterase tetramer suggested by x-ray crystallography. J Biol Chem 1999; 274:30370-6. [PMID: 10521413 DOI: 10.1074/jbc.274.43.30370] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acetylcholinesterase, a polymorphic enzyme, appears to form amphiphilic and nonamphiphilic tetramers from a single splice variant; this suggests discrete tetrameric arrangements where the amphipathic carboxyl-terminal sequences can be either buried or exposed. Two distinct, but related crystal structures of the soluble, trypsin-released tetramer of acetylcholinesterase from Electrophorus electricus were solved at 4.5 and 4.2 A resolution by molecular replacement. Resolution at these levels is sufficient to provide substantial information on the relative orientations of the subunits within the tetramer. The two structures, which show canonical homodimers of subunits assembled through four-helix bundles, reveal discrete geometries in the assembly of the dimers to form: (a) a loose, pseudo-square planar tetramer with antiparallel alignment of the two four-helix bundles and a large space in the center where the carboxyl-terminal sequences may be buried or (b) a compact, square nonplanar tetramer that may expose all four sequences on a single side. Comparison of these two structures points to significant conformational flexibility of the tetramer about the four-helix bundle axis and along the dimer-dimer interface. Hence, in solution, several conformational states of a flexible tetrameric arrangement of acetylcholinesterase catalytic subunits may exist to accommodate discrete carboxyl-terminal sequences of variable dimensions and amphipathicity.
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Affiliation(s)
- Y Bourne
- CNRS, Unité Propre de Recherche 9039, Architecture et Fonction des Macromolécules Biologiques, Institut de Biologie et Microbiologie Structurale, F-13402 Marseille Cedex 20, France
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Tsuji S, Anglade P. Hundredth Anniversary of the “Synapse”: II. Study of the Cholinergic Synapse. Zoolog Sci 1997. [DOI: 10.2108/zsj.14.539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Cohen SG, Lieberman DL, Hasan FB, Cohen JB. 1-Bromopinacolone, an active site-directed covalent inhibitor for acetylcholinesterase. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)45347-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Hasan F, Elkind J, Cohen S, Cohen J. Cationic and uncharged substrates and reversible inhibitors in hydrolysis by acetylcholinesterase (EC 3.1.1.7). The trimethyl subsite. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(18)43345-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Mansfield DH, Webb G, Clark DG, Taylor IE. Partial purification and some properties of a cholinesterase from bush bean (Phaseolus vulgaris L.) roots. Biochem J 1978; 175:769-77. [PMID: 743233 PMCID: PMC1186137 DOI: 10.1042/bj1750769d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A cholinesterase was partially purified from bush bean (Phaseolus vulgaris L.) roots by using acridinium-based ligand affinity chromatography. The procedure gave a 78-fold increase in specific activity, although at least three inactive contaminants remained. The enzyme activity was maximal against acetyl esters of choline and was inhibited by neostigmine. Di-isopropyl phosphorofluoridate completely inhibited activity at concentrations greater than 0.1 mM. The catalytic centre activity was 2 X 10(-4) times that of electric eel acetylcholinesterase. Cholinesterase activity appeared as a peak (s = 4.2 +/- 0.1 S) after isokinetic sedimentation. The Stokes radius was 4.00 nm and the apparent molecular weight was 72700 +/- 1900. The smallest active and native form of the enzyme appeared to be a monomer. This contrasts with animal acetylcholinesterases, in which the smallest active and native forms are multimeric.
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Johnson CD, Smith SP, Russell RL. Electrophorus electricus acetylcholinesterases; separation and selective modification by collagenase. J Neurochem 1977; 28:617-24. [PMID: 192853 DOI: 10.1111/j.1471-4159.1977.tb10433.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Das PK, Lo EH, Goedde HW. Heterogeneity and partial purification of human erythrocyte membrane acetylcholinesterase. HOPPE-SEYLER'S ZEITSCHRIFT FUR PHYSIOLOGISCHE CHEMIE 1977; 358:149-57. [PMID: 844798 DOI: 10.1515/bchm2.1977.358.1.149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Triton X-100 solubilised human erythrocyte acetylcholinesterase (E0), when subjected to chromatography on Sephadex G-200, showed one enzyme activity peak (Eg) and a number of protein peaks (Pg). The same sample could be separated into several subfractions of enzyme activity on DEAE-cellulose by gradient elution with increasing sodium chloride. When the gel filtered enzyme peak (Eg) alone was rechromatographed on an ion-exchange column under identical conditions, it showed only one enzyme peak. But when Eg in combination with protein peaks (Pg) without enzyme activity is rechromatographed as a physical mixture on a DEAE-cellulose column under the same conditions, the preparation could again be resolved into at least two fractions with enzyme activity. 2) Disc electrophoresis of fractions from DEAE-cellulose chromatography separated multiple bands which differ significantly from those produced by electrophoresis of E0. This suggests that E0 had undergone some form of conformational modification during the ion-exchange chromatography. However, this modification of E0 was avoided, if it was subjected to Sephadex G-200 chromatography before the DEAE-cellulose step. 3) A three-step technique (fractionation on Sephadex G-200, DEAE-cellulose chromatography and electrofocusing) has been performed for the purification of erythrocyte acetylcholinesterase. An enzyme preparation of high purity with a specific activity of 81 U/mg of protein was obtained.
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Henderson NS. Acetylcholinesterase isozymes in developing mouse tissues. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1977; 199:41-50. [PMID: 839187 DOI: 10.1002/jez.1401990106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Several isozymes of acetylcholinesterase are separated by 10% acrylamide gel electrophoresis of mouse blood, brain, heart, muscle and tongue tissues. Two isozymes migrating near the origin are described which show changes in relative activity during development. The faster of the two bands is proportionately higher in concentration in embryonic tissues and is highly specific for the acetylthiocholine iodide substrate. This isozyme corresponds to the erythrocyte membrane AChE in electrophortic mobility and substrate specificity. The slower of the two bands is predominant in adult tissues and exhibits considerable cross reaction with the butyrylthiocholine iodide substrate. During embryonic and postnatal developmental stages there is a gradual shift from the faster migrating isozyme toward a predominance of the slower migrating isozyme.
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OZAKI HIRONOBU. MOLECULAR PROPERTIES AND DIFFERENTIATION OF ACETYLCHOLINESTERASE IN SEA URCHIN EMBRYOS*. Dev Growth Differ 1976. [DOI: 10.1111/j.1440-169x.1976.00245.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
A relatively simple method is described by which cholinesterase was purified about 19000-fold starting from horse serum. Typically 20 litres of serum were processed to yield 15-18mg of electrophoretically pure cholinesterase in the form of an active salt-free dry powder. The method included two stages: fractionation with (NH(4))(2)SO(4) and ion-exchange chromatography. The (NH(4))(2)SO(4) stage included, in principle, the acid (pH3) step of the Strelitz (1944) procedure. The step took advantage of the stabilizing effect that 33%-satd. (NH(4))(2)SO(4) has on cholinesterase activity at pH3 and it is recognized that in the absence of (NH(4))(2)SO(4) the enzyme is rapidly destroyed at pH3. Cholinesterase was significantly more stable to pH3.0 at 2 degrees C than at 24 degrees C, and the acid step was done at both temperatures. The specific activities of the final products obtained by way of acid steps were the same at either temperature, thus indicating that the step has not harmed the enzyme active sites. The product from the first two stages was purified over 18000-fold and was 85-90% cholinesterase. The remaining impurities were removed by preparative gel electrophoresis. The product was about 40% more active and contained 40% more active sites per unit weight than electrophoretically pure cholinesterase prepared from partially purified commercial starting material. Although the number of active sites per molecule was not determined with certainty, a value of at least 3 and possibly 4 was indicated. The partial specific volumes were determined with a precision density meter, on the ultracentrifuge and from the amino acid and carbohydrate composition. The values by these independent methods were 0.688, 0.71 and 0.712ml/g, respectively. The amino acid and carbohydrate composition was determined. The cholinesterase contained 17.4% carbohydrate including 3.2% N-acetylneuraminic acid.
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Crone HD. Ion-exclusion effects on the chromatography of acetylcholinesterase and other proteins on agarose columns at low ionic strength. J Chromatogr A 1974. [DOI: 10.1016/s0021-9673(00)97197-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Husain SS, Mautner HG. The purification of choline acetyltransferase of squid-head ganglia. Proc Natl Acad Sci U S A 1973; 70:3749-53. [PMID: 4521199 PMCID: PMC427320 DOI: 10.1073/pnas.70.12.3749] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Choline acetyltransferase (EC 2.3.1.6) isolated from the head ganglia of squid could be purified by use of mercurial-Sepharose columns as well as Sepharose columns to which the enzyme inhibitor p-(m-bromophenyl)vinyl pyridinium had been attached. These columns, in conjunction with 30-55% ammonium sulfate precipitation, 40-30% ammonium sulfate extraction, chromatography on sulfopropyl-Sephadex and on cellulose phosphate and hydroxylapatite columns, led to the isolation of three factions of choline acetyltransferase ranging in activity from 1000 to 4000 mumole/mg of protein/per hr. Polyacrylamide gel electrophoresis suggests that two of these fractions are homogeneous. The squid choline acetyltransferase is different from the mammalian-brain enzymes in having a larger molecular weight under the conditions used and in being relatively poorly inhibited by styryl pyridinium compounds.
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Powell JT, Bon S, Rieger F, Massoulié J. Electrophorus acetylcholinesterase: a glycoprotein; molecular weight of its subunits. FEBS Lett 1973; 36:17-22. [PMID: 4747597 DOI: 10.1016/0014-5793(73)80327-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Hopff WH, Riggio G, Waser PG. Affinity chromatography of acetylcholine acetyl-hydrolase. EC 3.1.1.7. A new straight chain aliphatic inhibitor. FEBS Lett 1973; 35:220-2. [PMID: 4744390 DOI: 10.1016/0014-5793(73)80289-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Kumar V, Elliott WB. Acetylcholinesterase from a non-membrane source (Bungarus fasciatus venom). PREPARATIVE BIOCHEMISTRY 1973; 3:569-82. [PMID: 4205584 DOI: 10.1080/00327487308061539] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Lüllmann H, Preuner J. Effect of diisopropylfluorophosphate, edrophonium and a stabilizing agent on the conformation of acetylcholinesterase. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 1973; 280:339-51. [PMID: 4274701 DOI: 10.1007/bf00506627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Hall ZW. Multiple forms of acetylcholinesterase and their distribution in endplate and non-endplate regions of rat diaphragm muscle. JOURNAL OF NEUROBIOLOGY 1973; 4:343-61. [PMID: 4724813 DOI: 10.1002/neu.480040404] [Citation(s) in RCA: 433] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Eldefrawi ME, Eldefrawi AT. Characterization and partial purification of the acetylcholine receptor from Torpedo electroplax. Proc Natl Acad Sci U S A 1972; 69:1776-80. [PMID: 4505655 PMCID: PMC426800 DOI: 10.1073/pnas.69.7.1776] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Binding of acetylcholine in the concentration range 1 nM-1 muM was measured by equilibrium dialysis to a particulate preparation of Torpedo electroplax, without or with prior treatment of the tissue with one of three chemical modifying reagents. Significant reduction in binding of acetylcholine resulted after treatment with 1,4-dithiothreitol, p-chloromercuribenzoate, or p-(trimethylammonium)-benzenediazonium fluoroborate. Partial reversal of the reduction in binding occurred when dialysis was performed in the presence of 5,5'-dithiobis-(2-nitrobenzoic acid) or potassium ferricyanide (in the case of treatment with dithiothreitol), and 2-mercaptoethanol (in the case of treatment with p-chloromercuribenzoate). It is concluded that the functional acetylcholine-receptor macromolecule of Torpedo electroplax has disulfide bond(s), sulfhydryl group(s), and one or more of the amino acids vulnerable to diazotization by p-(trimethylammonium)-benzenediazonium fluoroborate. This, plus the effect of phospholipase C (EC 3.1.4.3) in elimination of detectable binding of acetylcholine after electrofocusing, is additional evidence that the functional acetylcholine receptor is a phospholipoprotein or a phospholipid-protein complex, which has a low isoelectric point of 4.5 +/- 0.2, yet is denatured by exposure to low pH for 24 hr. Due to this adverse effect, recovery of binding of acetylcholine after electrofocusing, as detected by equilibrium dialysis or ultrafiltration, is only 23% and, so far, only 6.3-fold purification of functional acetylcholine receptors by this technique is possible. Three or two forms of acetylcholinesterase (EC 3.1.1.7), whose peaks have isoelectric points ranging from 4.3 to 7.2, appear after electrofocusing of Torpedo extracted with 1% Triton X-100 or Lubrol, respectively. The major peak in either preparation has an isoelectric point of 5. Although the peaks of the functional acetylcholine receptors and of acetylcholinesterase of Torpedo electroplax are separable by electrofocusing, it has not been possible to isolate fractions that contain functional receptors but that are free of acetylcholinesterase. The opposite is possible.
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Rosenberry TL, Chang HW, Chen YT. Purification of Acetylcholinesterase by Affinity Chromatography and Determination of Active Site Stoichiometry. J Biol Chem 1972. [DOI: 10.1016/s0021-9258(19)45593-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Chan SL, Shirachi DY, Trevor AJ. Purification and properties of brain acetylcholinesterase (EC 3.1.1.7). J Neurochem 1972; 19:437-47. [PMID: 4621977 DOI: 10.1111/j.1471-4159.1972.tb01353.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Grafius MA, Bond HE, Millar DB. Acetylcholinesterase interaction with a lipoprotein matrix. EUROPEAN JOURNAL OF BIOCHEMISTRY 1971; 22:382-90. [PMID: 5125357 DOI: 10.1111/j.1432-1033.1971.tb01555.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Abstract
By using two methods of titration, the number of active sites in acetylcholinesterase was determined. Either stepwise inhibition of the enzyme by an irreversible inhibitor, namely di-isopropyl phosphorofluoridate, or direct measurement of the concentration of active sites by titration with o-nitrophenyl dimethylcarbamate yielded an equivalent weight of approx. 130000 for an active site in acetylcholinesterase. This indicates two sites per molecule, since the native enzyme has a molecular weight of 260000.
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In vitro excitation of purified membrane fragments by cholinergic agonists : III. Comparison of the dose-response curves to decamethonium with the corresponding binding curves of decamethonium to the cholinergic receptor. J Membr Biol 1971; 6:58-80. [PMID: 24173289 DOI: 10.1007/bf01874114] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/1970] [Revised: 05/12/1971] [Indexed: 10/25/2022]
Abstract
The reversible binding of(14)C-decamethonium (Deca) to excitable microsacs prepared from the electric tissue ofElectrophorus electricus is followed by an ultracentrifugal assay. α-Bungarotoxin, a snake venom toxin, blocks irreversibly the binding of(14)C-Deca. The displacement is partial. The fraction of(14)C-Deca displaced by α-bungarotoxin corresponds to molecules of Deca bound to the cholinergic receptor site, whereas the fraction of(14)C-Deca bound in the presence of α-bungarotoxin corresponds to molecules bound to the catalytic site of acetylcholinesterase (AcChE). The total number of cholinergic receptor sites is found to be close but not identical to the total number of catalytic sites of AcChE.On the same preparation of microsacs, the binding of(14)C-Deca and the permeability response corresponding to a given concentration of Deca are measured as a function of increased concentration of Deca. The dose-response curve and the binding curve superimpose almost exactly; in other words, the "apparent" affinity of Deca coincides with its "real" affinity. Displacement of(14)C-Deca byd-tubocurarine gives an "apparent" affinity ford-tubocurarine which coincides as well with its "real" affinity.The transport properties of the ionophore controlled by one Deca binding site are estimated.
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Massoulié J, Rieger F, Tsuji S. [Solubilization of electric organ acetylcholinesterase from eels. Action of trypsin]. EUROPEAN JOURNAL OF BIOCHEMISTRY 1970; 14:430-9. [PMID: 5488757 DOI: 10.1111/j.1432-1033.1970.tb00307.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Nachmansohn D. Proteins in excitable membranes: their properties and function in bioelectricity are discussed. Science 1970; 168:1059-66. [PMID: 4392552 DOI: 10.1126/science.168.3935.1059] [Citation(s) in RCA: 93] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Abstract
A rabbit antiserum against commercially available Electrophorus electricus acetylcholinesterase has been prepared. Five precipitation bands were distinguished by immunoelectrophoresis, but only three of these contained demonstrable enzyme activity. In an in vitro system, activity of the commercial enzyme or of highly purified acetylcholinesterase was inhibited by 70-82 per cent after incubation with antiserum. Antibody specificity was demonstrated by the absence of serological cross reactions or enzyme inhibition with bovine erythrocyte acetylcholinesterase or horse serum cholinesterase.
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Chapter 21. Molecular Basis of Drug Action. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1969. [DOI: 10.1016/s0065-7743(08)60661-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Changeux JP, Leuzinger W, Huchet M. Specific binding of acetylcholine to acetylcholinesterase in the presence of eserine. FEBS Lett 1968; 2:77-80. [PMID: 11946273 DOI: 10.1016/0014-5793(68)80105-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- J -P. Changeux
- Institut Pasteur, Service de Biochimie Cellulaire, Paris, France
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Nachmansohn D. Proteins in bioelectricity: the control of ion movements across excitable membranes. Proc Natl Acad Sci U S A 1968; 61:1034-41. [PMID: 4301146 PMCID: PMC305432 DOI: 10.1073/pnas.61.3.1034] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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