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

Circulating lipid levels and lipoprotein patterns in the Syrian hamster were determined at various times after subcutaneous inoculation with simian virus 40 (SV40) strain F, strain A-2895, or Fortner melanoma tumor cells. SV40 F tumors induced a rapid triphasic elevation of serum total lipids through inhibition of prebeta lipoprotein catabolism. Alpha lipoprotein levels declined in proportion to tumor mass. Liver wet weight and total lipid content increased significantly, but a normal rate of 3H-glycerol incorporation into polyanion precipitable (prebeta) serum lipoprotein was maintained. Determination of serum endogenous lipase, lecithin:cholesterol acyltransferase (LCAT), and cholinesterase activities indicated that these enzymes were not primarily responsible for the tumor-induced hyperlipidemia. Tumor-bearing animals also had selectively increased rates of protein and lipid excretion into the urine, with no evidence of gross hepatocellular or kidney damage. Growth of SV40 A-2895 tumors in hamsters resulted in a large increase in the rate of prebeta lipoprotein synthesis and degradation. Circulating prebeta lipoprotein levels were elevated much later in these animals, subsequent to a marked decrease in LCAT activity. Quite different results were obtained with Fortner melanoma, even large tumors having only a moderate effect on serum total lipid levels and lipoprotein patterns in the Syrian hamster.
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PMID:Effect of simian virus 40 subcutaneous tumors on circulating lipids and lipoproteins in the Syrian hamster. 16 32

The behaviour of several dehydrogenases(succino-, beta-glycerophosphate-, lactate-, alcohol-, beta-hydroxibutyric acid-, glucose-6-phosphate-, isocitronic acid-dehydrogenase, monoamino-oxidase, and gamma-aminobutyric acid-transaminase) and of several hydrolytic enzymes (non-specific esterase, lipase, acetylcholin-, butyrylcholinesterase, alkaline phosphatase and leucinaminopeptidase) was investigated in the neurons of NSO and NPV, in the infundibulum and in the neurohypophysis and the innervation of the neurons (acetylcholinesterase, monoamino-oxidase, catecholamines) by unmilked and milked cows. The milking stimulus influences the metabolism especially in the neurosecretory cells of the NPV. After the milking stimulus the activity of oxydative enzymes is above all very increased, the anaerobic way of the output of energy is after that also higher. The building up of the carbohydrates through glycolyse in the neurosecretory cells of the NPV after the milking stimulus is increased. The possible participation of the investigated hydrolytic enzymes on the metabolism of the neurosecretory cells is discussed. The neurons of the NPV were innervated for the most part adrenergic. It is discussed the participation of the enzymes succinodehydrogenase and monoaminooxidase on the hormone release in the neurohypophysis.
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PMID:[Enzymhistochemical investigations on the hypothalamo-neurohypophysial system of unmilked and milked cows (author's transl)]. 82 94

A screening aimed at obtaining a cholinesterase inhibitor of microbial origin was carried out using Pseudomonas butyrylcholinesterase. A mycelium-extract of a fungus strain, belonging to the genus Penicillium, was found to produce such an enzyme inhibitor. The inhibitor was purified and crystallized as colorless leaflets. From physical and chemical studies, the inhibitor was identified as being identical with an antibiotic, mycelianamide, though this compound was not known to have enzyme inhibitor activity. The kinetics of the inhibition of Pseudomonas butyrylcholinesterase were also studied. Horse serum cholinesterase and hog liver carboxylesterase were also inhibited by the isolated Penicillium C-81 inhibitor, but lipase and acetylcholinesterase were not.
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PMID:A butyrylcholinesterase inhibitor produced by Penicillium sp. no. C-81 and its identity with mycelianamide. 95 41

Chlorpyrifos, an organophosphate insecticide, has often been used as a termite-control agent since the advent of regulatory measures against the use of chlordanes in September 1986. A current concern is hazards such as organophosphorus poisoning among termite-control workers. In this study, the blood cholinesterase activity, the number of hours engaged in termite-control work, general conditions, and various test values were examined regularly in eight workers at a termite-control office. The results are summarized as follows. 1. The plasma cholinesterase level was within the normal range from October 1986 until April 1987 in all workers, but started decreasing after May following the initiation of the full-scale termite-control season. It remained lower than the normal range (0.6 pH) from June until August in five of the six termite-control workers. The lowest level observed during this period was less than 50% of the mean value for each worker prior to the busy season in the six termite-control workers and was less than 10% of the pre-season values in three of them. In two workers, engaged mainly in sales, the plasma cholinesterase activity remained higher than in termite-control workers throughout the season. The lowest level in this minimally-exposed group during this period was not less than 50% of the mean value for each worker before the busy season. With the arrival of the off season, the level began to recover and returned to normal in all workers in January 1988. 2. The red cell cholinesterase activity remained within the normal range throughout the observation period, but it was generally low during the busy season from June to September and relatively high during the off season from December 1987 to January 1988. On the average, the red cell cholinesterase activity during the season was about 30% lower than that in the off season. 3. No marked subjective or objective abnormalities were seen in the workers. The results of other tests were generally normal, although a slight decrease in the red cell and white cell counts as well as abnormalities in serum lipid and lipase were noted in some workers. Further observations are necessary. 4. A significant negative correlation was noted between the number of hours engaged in termite-control work and variations in the plasma cholinesterase activity.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Variations in blood cholinesterase activity and exposure to chlorpyrifos in termite-control workers]. 169 4

The structure and some functional sites of human milk bile salt activated lipase (BAL) were studied by cDNA cloning and chemical analysis of the enzyme. Eighteen cDNA clones of human BAL were identified from lactating human breast cDNA libraries in lambda gt11 and lambda gt10 with antibody and synthetic oligonucleotides as probes. The sequence of four clones was sufficient to construct a 3018-bp BAL cDNA structure. This sequence codes for an open reading frame of 742 amino acid residues. There is a putative signal sequence of 20 residues which is followed by the amino-terminal sequence of BAL, and the mature BAL contains 722 amino acid residues. The cDNA sequence also contains a 678-base 5'-untranslated sequence, a 97-base 3'-untranslated region, and a 14-base poly(A) tail. The sequence of a 1.8-kbp insert of clone G10-4A differs from that of the other cDNA in that it contains a deletion of 198 bases (1966-2163) corresponding to 66 amino acid residues. By use of BAL cDNA as probe, it was found that the major molecular species of BAL mRNA in human mammary gland HBL-100 cells had a size of 2.9 kb and two minor species had sizes of 3.8 and 5.1 kb by Northern blot analyses. The deduced BAL protein structure contains in the carboxyl-terminal region 16 repeating units of 11 amino acids each. The repeating units have the basic structure Pro-Val-Pro-Pro-Thr-Gly-Asp-Ser-Gly-Ala-Pro with only minor substitutions. The amino acid sequence of human BAL is related to that of pancreatic lysophospholipase, cholesterol esterase, cholinesterase, acetylcholinesterase, and thyroglobulin. Ten of the 14 cyanogen bromide fragments of diisopropyl fluorophosphate inhibited human milk BAL were isolated, determined for N-terminal sequences, analyzed for amino sugars, and tested for some functional properties. These chemical studies established that the active site of human milk BAL is located at serine-194, the N-glycosylation site is present at asparagine-187, the O-glycosylation region is in the 16 repeating units near the C-terminus, and the heparin binding domain is in the N-terminal region. We have also determined the location of disulfide bridges as Cys64-Cys80 and Cys246-Cys257. The cyanogen bromide cleavage and the partial sequencing of CNBr peptides also confirmed the location of methionines in the polypeptide chain as well as the deduced cDNA sequence of BAL.
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PMID:Structure of human milk bile salt activated lipase. 198 41

To determine the active site residue, human milk bile-salt stimulated lipase (BSSL) was labelled with [3H]diisopropyl fluorophosphate (DFP). Partial sequence analysis of cyanogen bromide fragments (a total of 146 residues from 6 peptides) revealed 84% sequence identity with a putative rat lysophospholipase. Sequence analysis of a [3H]DFP-labelled peptide indicated that the active site serine was contained in the sequence Gly-Glu-Ser-Ala-Gly. In addition to similarity with rat lysophospholipase, this sequence showed homology with regions of human butyrylcholinesterase and electric ray acetylcholinesterase (68% identity). It is concluded that these proteins are members of a new supergene family.
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PMID:Human milk bile-salt stimulated lipase. Sequence similarity with rat lysophospholipase and homology with the active site region of cholinesterases. 199 11

The histidine residue essential for the catalytic activity of pancreatic cholesterol esterase (carboxylester lipase) has been identified in this study using sequence comparison and site-specific mutagenesis techniques. In the first approach, comparison of the primary structure of rat pancreatic cholesterol esterase with that of acetylcholinesterase and cholinesterase revealed two conserved histidine residues located at positions 420 and 435. The sequence in the region around histidine 420 is quite different between the three enzymes. However, histidine 435 is located in a 22-amino acid domain that is 47% homologous with other serine esterases. Based on this sequence homology, it was hypothesized that histidine 435 is the histidine residue essential for catalytic activity of cholesterol esterase. The role of His435 in the catalytic activity of pancreatic cholesterol esterase was then studied by the site-specific mutagenesis technique. Substitution of the histidine in position 435 with glutamine, arginine, alanine, serine, or aspartic acid abolished the ability of cholesterol esterase to hydrolyze p-nitrophenyl butyrate and cholesterol [14C]oleate. In contrast, mutagenesis of the histidine residue at position 420 to glutamine had no effect on cholesterol esterase enzyme activity. The results of this study strongly suggested that histidine 435 may be a component of the catalytic triad of pancreatic cholesterol esterase.
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PMID:Site-specific mutagenesis of an essential histidine residue in pancreatic cholesterol esterase. 199 99

The Ser-His-Asp triad is a well known structural feature of the serine proteases. It has also been directly observed in the catalytic sites of two lipases, whose high-resolution three-dimensional structures have been determined 1,2. Lipases show a wide variety of sizes, substrate and positional specificities, and catalytic rates 3. They achieve maximal catalytic rates at oil-water interfaces. The fungus Geotrichum candidum produces several different forms of lipases, two of which have been purified to homogeneity 4,5. Two lipase genes have been identified, cloned and sequenced 6,7. Both code for proteins of 544 amino acids with a total relative molecular mass of about 60,000 (Mr 60K). The two forms are 86% identical. Their isoelectric points differ slightly, being between 4.3 and 4.6. About 7% of the total Mr is carbohydrate. Until now, only a low resolution structure of GCL has been reported 8, but no high resolution structure has followed. We now report the three-dimensional structure of a lipase from G. candidum (GCL) at 2.2 A resolution. Unlike the other lipases and serine proteases, the catalytic triad of GCL is Ser-His-Glu, with glutamic acid replacing the usual aspartate. Although the sequence similarity with the other two lipases is limited to the region near the active-site serine, there is some similarity in their three-dimensional structures. The GCL is also an alpha/beta protein with a central mixed beta sheet whose topology is similar to that of the N-terminal domain of human pancreatic lipase. As in the other lipases 1,2, the catalytic site is buried under surface loops. Sequence comparisons with proteins from the cholinesterase family suggest that they also contain the Ser-His-Glu triad.
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PMID:Ser-His-Glu triad forms the catalytic site of the lipase from Geotrichum candidum. 206 69

Geotrichum candidum produces two extracellular lipases, I and II. A lipase II cDNA clone was isolated from a cDNA library by colony hybridization using the 32P-labeled fragment of lipase I cDNA isolated previously. The nucleotide sequence of lipase II cDNA determined by the dideoxy chain terminating method includes the N- and C-terminal amino acid sequences of lipase II, and the overall amino acid composition deduced from the cDNA coincides with that deduced on amino acid analysis of this protein. The cloned lipase II cDNA codes a protein of 544 amino acids and a part of the signal sequence of 13 amino acids. The peptide chain lengths of lipases I and II are the same, their overall identity being 84%. Furthermore, four Cys residues are completely conserved, which may participate in the formation of disulfide bridges. A homology search indicated that the G. candidum lipases and Candida cyclindracea lipase are homologous enzymes and that they are members of the cholinesterase family.
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PMID:cDNA cloning and characterization of Geotrichum candidum lipase II. 239 37

The experiment was carried out on Wistar rats receiving orally either oil or oily solution of methylbromophenvinfos (Polfos) either in a single dose of 0.5 LD50, or doses of 0.1 LD50 once daily for a period of 2, 4 or 6 weeks. The activities of cholinesterase (ChE), beta-glucuronidase (beta-glu), lipase and amylase were assayed in the blood serum, the activity of acetylcholinesterase (AChE)-in brain homogenates, and the activities of lipase and amylase-in homogenates of the pancreas. Cholinesterases were inhibited in the course of both acute and chronic poisoning with Polfos. During the acute poisoning a sharp increase in the activity of beta-glu in the blood serum, 1 and 2 h after the pesticide administration, was observed. Polfos inhibited lipase and amylase both after acute and chronic treatment.
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PMID:The effect of methylbromophenvinfos (Polfos) on some enzymes in vivo and in vitro. I. In vivo studies. 245 47


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