Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of high intake of vitamin C in the young growing rats under administration of nickel sulphate in toxic doses has been studied. Ingestion of nickel sulphate depresses the growth rates of rats, alters the vitamin C status in different tissues, inhibits certain enzymes of vitamin C metabolism and changes the activities of alkaline phosphatase and succinic dehydrogenase in the liver and kidney tissues. The acid phosphatase activity of liver, kidney and brain tissues of rats and glucose-6-phosphatase activity in liver, and serum GOT activity were stimulated, with reduction in the in the liver GOT activity. There is stimulation in the activities of rat brain inorganic pyrophosphatase and cholinesterase. Kidney tissues of rats were found to be more susceptible towards nickel toxicity as compared to the hepatic tissues in respect of morphological alterations. There is almost no alteration in the hepatic lipid composition. Administration of vitamin C in high doses to rats fed nickel salts in toxic doses can restore not only the growth rates but also certain enzyme activities to a significant extent.
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PMID:Biochemical studies on nickel toxicity in weanling rats -- influence of vitamin C supplementation. 23 Oct 18

A toxicological experiment on white male rats was carried out for one year. They received simultaneously per os nickel in doses 0.005 mg/kg and lead in doses 0.0025 mg/kg, equivalent respectively to the recommended by CMEA norms for nickel and hygienic norm for lead in drinking waters, as well as nickel and lead in doses 0.015 and 0.01 mg/kg, 0.015 and 0.1 mg/kg surpassing 3 and 4 times and 30 and 40 times the above mentioned norms or only nickel in doses 0.015 mg/kg, after which their effect on some enzyme indices was studied. Tests were made on: free sulfhydryl groups in blood serum, heart and liver; catalase activity of blood; cholinesterase activity and creatinphosphatase in blood serum; cytochromoxidase activity in liver and heart. It is established that in combined per os effect of nickel and lead in doses respectively 0.15 and 0.1 mg/kg and 0.015 and 0.01 mg/kg, as well as during independent effect of nickel with doses 0.015 mg/kg, occur disorders in the tissue breathing and oxyreduction processes. Nickel and lead in doses, equivalent to the hygienic norms, lead to no changes according to all studied indices.
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PMID:[The effect of chronic combined exposure to nickel and lead on the enzymatic indices in body uptake with the drinking water]. 136 56

Acetylcholinesterase (AchE: EC 3.1.1.7) was identified and purified from the hemolymph of the scorpion Heterometrus bengalensis. The purity of the enzyme was determined by polyacrylamide gel electrophoresis (PAGE). The molecular weight of the enzyme, determined by sodium dodecyl sulfate-PAGE, was 80,000. The purified AchE hydrolysed acetylthiocholine iodide, but it did not react with butyrylthiocholine iodide. BW284C51, a specific inhibitor of AchE, strongly inhibited the enzyme. The known inhibitor (tetramonoisopropylpyrophosphortetramide) of pseudocholinesterase did not produce any inhibition of the enzyme activity. The purified AchE of scorpion hemolymph was vulnerable to high substrate concentration. The presence of Cu2+ and Ni2+ reduced the enzyme activity, whereas the metal ion, Sn2+, enhanced AchE activity. Ca2+ produced neither inhibition nor activation. (Na+, K+)-ATPase and Mg2+-ATPase activities were greatly enhanced by the purified AchE.
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PMID:Acetylcholinesterase (EC 3.1.1.7), a neurotransmitter enzyme in scorpion hemolymph. 296 37

The interaction of spin-labeled metacyn, procaine, carbolin and bivalent cations (Ca2+, Co2+, Ni2+) with butyrylcholinesterase (BChE) was studied by ESR and enzyme kinetic methods. The effect of pH, ionic strength and organic solvent was analysed. Spin-labeled metacyn binds at the anionic site of BChE active centre. This complex is stabilized both with coulombic and hydrophobic interactions, ionizing group of active centre with pK 6-7 also affects the binding. Spin-labeled procaine appeared to be enzyme competitive inhibitor (Ki = 4 X 10(-5) M) and is located, most probably, at the same site. Activating effect of Ca2+ ions on BChE was confirmed. Simultaneous application of spin labels and paramagnetic ions demonstrates that cations Co2+ and Ni2+ bind with BChE in the close vicinity of spin-labeled inhibitor site. Paramagnetic cations are located more closely to the cationic part of the inhibitor molecule than to the hydrophobic one, and can be displaced by surplus of Ca2+ ions. The experimental data testify the model of anionic centre which consists of bivalent metal ions and aminoalcyl cationic group subsites and is located in a hydrophobic pocket of the enzyme surface.
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PMID:[Binding of reversible spin-labeled inhibitors with an butyrylcholinesterase active center]. 302 29

Human serum butyrylcholinesterase (BChE) has been converted into a stable but less active desensitized form when heated at 45 degrees C for 24 h. The desensitized BChE follows Michaelis-Menten kinetics, whereas native enzyme exhibits slightly negative cooperativity with respect to butyrylthiocholine binding. In this study, we investigated the effects of Ni2+, Co2+, and Mn2+ on the desensitized BChE. It is found that all three ions were noncompetitive inhibitors of the desensitized BChE, and Ki values have been determined as 7.816 +/- 1.060 mM, 48.722 +/- 4.635 mM, and 84.795 +/- 5.249 mM for Ni2+, Co2+, and Mn2+, respectively. In our previous study, these ions were linear mixed-type inhibitors of the native BChE. This finding confirms that desensitized BChE changes to a different conformation than native BChE. From the comparison of Ki values of the trace elements, it can be said that Ni2+ is a more effective inhibitor of the desensitized BChE than Co2+ and Mn2+.
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PMID:Effects of Ni(2+), Co(2+), and Mn(2+) on desensitized butyrylcholinesterase prepared from human serum. 1283 90

This paper describes a new method for the sensitive detection of cholinesterase inhibitors based on real-time monitoring using a piezoelectric biosensor. The cholinesterase inhibitor paraoxon was immobilized on the sensing surface via a chelate complex as the recognition element. At first, the conjugate of N-mercaptoundecanoic acid (MUA) with Nalpha,Nalpha-bis (carboxymethyl)-L-lysine (NTA-Lys) was chemisorbed to form a self-assembled monolayer on the surface of the gold electrode of the piezosensor. In the next step, paraoxon-spacer-hexahistidine conjugate was linked to the MUA-Lys-NTA layer via the chelate complex with Ni2+. The paraoxon-modified surface thus obtained was applied for the binding of human butyrylcholinesterase (BChE). Regeneration of the sensing surface was achieved by splitting the chelate complex with EDTA and depositing a fresh layer of Ni2+ followed by addition of the paraoxon-spacer-hexahistidine. In the presence of free inhibitors like diisopropylfluorophosphate (DFP), binding of BChE to the surface-bound paraoxon was decreased. In this way, a competitive affinity assay for organophosphorus compounds was developed. The limit of detection for DFP as a model compound was 10 nmol/l (ca. 2 microg/l). This new concept seems suitable for constructing biosensors for the group-specific detection of cholinesterase-inhibiting substances like insecticides in the field.
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PMID:New principle of direct real-time monitoring of the interaction of cholinesterase and its inhibitors by piezolectric biosensor. 1289 33

The effects of Ni2+, Co2+, and Mn2+ on human serum butyrylcholinesterase (BChE, acylcholine acylhydrolase E.C. 3.1.1.8) were investigated in this study. Inhibition kinetics of BChE were studied using butyrylthiocholine (BTCh) as substrate. The "1/v" versus "1/[BTCh]" plots in the absence (control plot) and in the presence of the metal ions intersected above 1/[BTCh]-axis for all trace elements. In addition, when the concentrations of the cations were increased at 4 mM BTCh, velocities decreased and drove to zero at high concentrations of the trace elements. These results demonstrate that Ni2+, Co2+, and Mn2+ are linear mixed-type inhibitors of BChE. alphaK(i) values have been determined as 53.20 mM,152.25 mM, and 190.24 mM for Ni2+, Mn2+, and Co2+, respectively, by using nonlinear regression analysis. From the comparison of alphaK(i) values of the trace elements, it can be said that BChE has more affinty to binding Ni2+ than Co2+ and Mn2+.
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PMID:The effects of Ni2+, Co2+, and Mn2+ on human serum butyrylcholinesterase. 1470 92

The enzymatic activity of acetylcholinesterase (AChE) has been shown to be altered by environmental contaminants such as metals. However, the available literature illustrates a background of contradictory results regarding these effects. Therefore, the main purpose of this study was to investigate the potential of five metal ions (nickel, copper, zinc, cadmium and mercury) to inhibit AChE activity in vitro. First, to accomplish this objective, the possible interference of metals as test toxicants in the Ellman's assay, which is widely used to assess AChE activity, was studied. The potential influence of two different reaction buffers (phosphate and Tris) was also determined. The results suggest that the selected metals react with the products of this photometric technique. It is impossible to ascertain the artefactual contribution of the interaction of the metals with the technique when measuring AChE inhibition. This constitutes a major obstacle in obtaining accurate data. The presence of phosphate ions also makes enzymatic inhibition difficult to analyse. Attending to this evidence, an assay using the substrate o-nitrophenyl acetate and Tris buffer was used to investigate the effects of metals on AChE activity. O-nitrophenyl acetate is also a substrate for esterases other than cholinesterases. It is therefore only possible to use it for the measurement of cholinesterase activity with purified enzymes or after a previous verification of the absence of other esterases in the sample tissue. Under these conditions, the results indicate that with the exception of nickel, all tested metals significantly inhibit AChE activity.
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PMID:Do metals inhibit acetylcholinesterase (AChE)? Implementation of assay conditions for the use of AChE activity as a biomarker of metal toxicity. 1624 21

Paraoxonase-1 (PON1) and cholinesterase (BChE) are two of the major human serum esterases. Although most of variation in PON1 activity results from genetic factors, there is growing evidence that environmental chemicals also modulate its activity. The aim of this study was to investigate whether environmental exposure to metal compounds has any influence on those esterases. A cross-sectional study was conducted in a representative sample of the general population of Andalusia, South of Spain. PON1 activity against different substrates (paraoxon, phenylacetate, diazoxon and dihydrocoumarin) and BChE were measured in serum from 536 healthy subjects. Potential associations of these esterases with metal compounds, age, sex and body mass index as well as life-style habits (smoking, alcohol drinking and food habits) were explored. Multiple linear regression analysis showed that blood lead levels were significantly associated with increased PON1 in serum regardless of the substrate used for the assay. Mercury also showed a significant and direct association with PON1 towards paraoxon and phenylacetate. In turn, cadmium and zinc levels were significantly associated with a decreased PON1 activity (zinc was associated with all PON1 activities and cadmium with PON1 towards paraoxon and diazoxon). Arsenic, nickel and manganese failed to be significantly associated with any of the PON1 activities assayed. PON1 192R alloform predicted significantly higher levels of arsenic and lead. BChE, however, was inversely associated with serum levels of manganese and zinc. These results suggest that PON1 and BChE activities are modulated by background exposure to metal compounds, which may have implications in public health given the defensive role played by both enzyme proteins against environmental toxicants. The potential underlying mechanisms merit further investigation.
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PMID:Interaction between human serum esterases and environmental metal compounds. 1939 62

The developmental neurotoxicity of organophosphates involves mechanisms other than their shared property as cholinesterase inhibitors, among which are excitotoxicity and oxidative stress. We used PC12 cells as a neurodevelopmental model to compare the effects of chlorpyrifos and diazinon on the expression of genes encoding glutamate transporters. Chlorpyrifos had a greater effect in cells undergoing nerve growth factor-induced neurodifferentiation as compared to undifferentiated PC12 cells, with peak sensitivity at the initiation of differentiation, reflecting a global upregulation of all the glutamate transporter genes expressed in this cell line. In differentiating cells, chlorpyrifos had a significantly greater effect than did diazinon and concordance analysis indicated no resemblance in their expression patterns. At the same time, the smaller effects of diazinon were highly concordant with those of an organochlorine pesticide (dieldrin) and a metal (divalent nickel). We also performed similar evaluations for the cystine/glutamate exchanger, which provides protection against oxidative stress by moving cystine into the cell; again, chlorpyrifos had the greatest effect, in this case reducing expression in undifferentiated and differentiating cells. Our results point to excitotoxicity and oxidative stress as major contributors to the noncholinesterase mechanisms that distinguish the neurodevelopmental outcomes between different organophosphates while providing a means whereby apparently unrelated neurotoxicants may produce similar outcomes.
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PMID:Transcriptional profiles for glutamate transporters reveal differences between organophosphates but similarities with unrelated neurotoxicants. 2060 Jun 79


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