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 effect of organic and inorganic forms of nitrogen on biomass accumulation and cholinesterase synthesis was studied with Arthrobacter simplex var. cholinesterasus. The culture assimilates nitrogen of ammonium compounds better than other forms of inorganic nitrogen; the best nitrogen source for biosynthesis of cholinesterase is ammonium phosphate. Nitrogen of nitrates is not assimilated. The amount of biomass is almost twice as high on the medium with peptone, casein or casein hydrolysate as on the medium with mineral nitrogen, while the activity of cholinesterase on these nitrogen sources decreases 1.5--2.0 times. Yeast extract as a nitrogen source increases biomass accumulation by a factor of 2.5 and does not supress synthesis of cholinesterase. The concentration of the enzyme synthesized per unit biomass on the medium with yeast extract is the same as on the medium containing ammonium phosphate. The effect of amino acids and amides, i.e. beta-alanine, proline, amides of aspartic and glutamic acids, and their mixtures, is similar to the action of yeast extract: they stimulate biomass accumulation and do not inhibit synthesis of the enzyme. Other amino acids supress synthesis of cholinesterase. The amount of accumulated biomass in the presence of glutamic acid is twice as high as in the case of any other amino acid, and three times as high as on the medium containing ammonium phosphate. Similar action of glutamic acid is manifested when it is used in mixtures with other amino acids. On the medium containing glutamic acid as a sole source of nitrogen, an increase in biomass production is accompanied with a decrease in biosynthesis of the enzyme by 50%. Repression of the biosynthesis is less if glutamic acid is added in mixtures with proline, beta-alanine and asparagine.
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PMID:[Effect of nitrogen source on growth of Arthrobacter simplex and its biosynthesis of cholinesterase]. 97 79

Nine esterase fractions hydrolyzing 1-naphthylacetate were revealed in Triton X-100-solubilized extracts from aphides homogenates by polyacrylamide gel electrophoresis. The less mobile fractions 1-4 were identified as cholinesterases, using specific inhibitors--eserine and the cationic phosphoorganic inhibitor Gd-42; fractions 5-7 were related to carboxylesterases, using specific inhibition by triorthocresylphosphate and O,O-dimethyl (2,2-dichlorvinyl)phosphate. The most mobile fractions 8-9 which were resistant to the inhibitors, were classified as arylesterases. The aphis cholinesterase fractions revealed the highest mobility; the activity of carboxylesterase fractions was lower. Thiophosphonate--C8H17O(CH3)P(O)-SCH2SCH2COOCH3 was found to be a highly efficient selective inhibitor of aphis carboxylesterase, i. e. the kII values for carboxylesterase and cholinesterase were equal to 10(8) and 10(5) M-1 min-1, respectively. The thiophosphoorganic derivatives containing a beta-alanine residue in the cleaved part are more specific to acetylcholinesterase and carboxylesterase than those containing a valine residue. Studies with enanthiomers--C2H5O(CH3)P(O)SCH2CONHCH2CH2COOC2H5 and (C2H5O)2P(O)SCH2CONHCH(iC3H7)COOC2H5 have demonstrated that the asymmetry due to the central phosphorus atom is more essential for the acetylcholinesterase and carboxylesterase activities than that connected with the carbon atom in the cleaved part of the inhibitor molecule. During the interaction of the enanthiomers with the asymmetric phosphorus the stereospecificity of acetylcholinesterase is much higher than that of carboxylesterase. In terms of stereospecificity of the esterase site aphis acetylcholinesterase is is similar to its mammalian counterpart, while carboxylesterase from the same source is rather close to mammalian butyrylcholinesterase.
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PMID:[Multiple molecular forms of esterases from grass aphids inhibitory identification and stereospecificity]. 663 87

L-Carnitine (L-C) is involved in the transport of acyl groups into mitochondria for beta-oxidation, although its role in the adult brain is still uncertain. We have shown before that the uptake of L-carnitine into cultured rat cortical neurones was dependent on temperature as well as the Na gradient and is inhibited by compounds resembling its structure, like gamma-aminobutyric acid (GABA), but most potently by specific GABA uptake blockers. In this study we have characterised this uptake process further. We have shown that the uptake of L-carnitine may be dependent on Cl ions, in addition to Na ions, but non on Ca ions. The L-C uptake was inhibited by substituent anions in the order gluconate (83%) > isethionate (32%), with propionate being ineffective, whereas GABA uptake was inhibited most potently by propionate substitution (79%) and equally by isethionate and gluconate (67%). This L-C uptake process was not affected by the amino acids, glutamine or lysine, up to 1 mM concentration, although beta-alanine at 500 microM caused a 38% inhibition. The uptake of L-C was also significantly inhibited by structurally-related compounds, with a carbon chain length of three to six atoms, possessing an amine group and/or a carboxyl group. At a concentration of 500 microM, 3-aminopropane sulphonic acid (53%), gamma-butyrobetaine (31%), gamma-hydroxybutyric acid (34%) and 4 methylaminobutyric acid (33%). Other compounds were effective only at the lower concentration of 10 microM, such as butyric acid (25%), nicotinic acid (26%), isonicotinic acid (26%), hexanoic acid (23%) and at 100 microM, like 6-aminocapric acid (22%). Drugs suggested to affect membrane properties, such as chlorpromazine, was without effect at 1 or 10 microM, whereas flunarizine (FLU) at 1 microM inhibited both L-C (24%) and GABA uptake (17%). Other drugs like the cholinesterase inhibitors, tacrine and eserine, also had a small inhibitory effect on L-C uptake, reducing it at 1 microM by 22 and 21% respectively, although higher concentrations were toxic (> 100 microM). Pretreatment of the cells with neuraminidase (50 U ml-1, 10 min) reduced the subsequent uptake of both L-C (18%) and GABA (42%). Hypoxia (3 h) also significantly attenuated L-C uptake (42%), however part of these effects were related to the loss of cell viability. In summary, L-C uptake occurs by a complex mechanism which at least in part may occur by a Na/Cl cotransport mechanism, which could be similar, to that of GABA or may even in part occur via the GABA transporter.
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PMID:Structural, metabolic and ionic requirements for the uptake of L-carnitine by primary rat cortical cells. 881 42