Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.1.4 (deaminase)
5,113 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of chemical modification on the acetylcholinesterase and the aryl acylamidase activities of purified acetylcholinesterase from electric eel and basal ganglia was investigated in the presence and absence of acetylcholine, the substrate of acetylcholinesterase, and 1,5-bis[4-(allyldimethylammonium)phenyl]pentan-3-one dibromide (BW284C51), a reversible competitive inhibitor of acetylcholinesterase. Trinitrobenzenesulfonic acid, pyridoxal phosphate, acetic anhydride, diethyl pyrocarbonate, and 2-hydroxy-5-nitrobenzyl bromide under specified conditions inactivated both acetylcholinesterase and aryl acylamidase in the absence of acetylcholine and BW284C51. Chemical modifications in the presence of acetylcholine and BW284C51 by all the above except diethyl pyrocarbonate selectively prevented the loss of acetylcholinesterase but not aryl acylamidase activity; modification by diethyl pyrocarbonate in the presence of acetylcholine and BW284C51 prevented the loss of both acetylcholinesterase and aryl acylamidase activities. Treatment with N-acetylimidazole resulted in the inactivation of acetylcholinesterase and the activation of aryl acylamidase. These changes in both the activities could be prevented by acetylcholine and BW284C51. Modification by phenylglyoxal, 2,4-pentanedione, or N-ethylmaleimide did not affect the enzyme activities. Indophenylacetate hydrolase activity followed a pattern similar to that of acetylcholinesterase in all the above modification studies. The results suggested essential lysine, tyrosine, tryptophan, and histidine residues for the active center of acetylcholinesterase and essential lysine, histidine, and tryptophan residues for the active center of aryl acylamidase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Chemical modification of acetylcholinesterase from eel and basal ganglia: effect on the acetylcholinesterase and aryl acylamidase activities. 638 42

Aminoacylase (EC 3.5.1.14) from Aspergillus oryzae was purified from a commercially available crude material by heat treatment, precipitation by polyethyleneimine and ammoniumsulfate, gel chromatography and preparative disc-gel-electrophoresis. The purified product was homogenous as judged by polyacrylamide gel electrophoresis. SDS-gel electrophoresis, polyacrylamide-gel-gradient electrohoresis, gel chromatography and amino acid analysis demonstrated the enzyme to be composed of two subunits with Mr of 36 600. The kinetic properties of the enzyme were studied with chloracetyl derivatives of alanine, phenylalanine, methionine, leucine, norleucine and tryptophan. The pH optimum of the acylase activity with chloroacetyl-alanine as substrate is at pH 8.5. Acyl derivatives of hydrophobic amino acids are preferred substrates. The enzyme has no dipeptidase activity. Aminoacylase is not inhibited by SH-blocking agents and no SH-groups could be detected with Ellman's reagent in the native and denatured enzyme. The enzyme activity is insensitive to phenylmethylsulfonyl fluoride and N-alpha-p-tosyl-L-lysine chloromethyl ketone. The microbial acylase is zince metallo enzyme. Mental chelating agents are strong inhibitors; it is further inhibited by Cd2+, Mn2+ and activated by Co2+. The properties of pig kidney and Aspergillus acylase are compared.
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PMID:Aminoacylase from Aspergillus oryzae. Comparison with the pig kidney enzyme. 677 95

Aspartylglucosaminidase (AGA, EC 3.5.1.26) is a dimeric lysosomal hydrolase involved in the degradation of glycoproteins. The synthesized precursor polypeptide of AGA is rapidly activated in the endoplasmic reticulum by proteolysis into two subunits. Expression of the alpha- and beta-subunits of AGA in separate cDNA constructs showed that independently folded subunits totally lack enzyme activity, and even when co-expressed in vitro they fail to produce an active heterodimer of the enzyme. Both of the subunits are required for the enzyme activity, and the immediate interaction of the subunits in the endoplasmic reticulum is necessary for the correct folding of the dimeric enzyme molecule. The specific amino acid residues essential for the active site of the AGA enzyme were further analyzed by site-directed mutagenesis and in vitro expression of mutagenized constructs. Replacement of Thr206, the most amino-terminal residue of the beta-subunit, with Ser resulted in a complete loss of enzyme activity without influencing intracellular processing or transport of the mutant polypeptide to the lysosomes. Analogously, replacement of the most amino-terminal tryptophan, Trp34 with Phe or Ser in the alpha-subunit, resulted in a totally inactive enzyme without influencing the intracellular processing or stability of the polypeptide. These results suggest that the catalytic center of this amidase is formed by the interaction of the amino-terminal parts of two subunits and requires both Trp34 in the alpha-subunit and Thr206 in the beta-subunit.
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PMID:Immediate interaction between the nascent subunits and two conserved amino acids Trp34 and Thr206 are needed for the catalytic activity of aspartylglucosaminidase. 787 64

Growth promotion and iron transport studies revealed that certain alpha-keto acids generated by amino acid deaminases, by enterobacteria of the Proteus-Providencia-Morganella group (of the tribe Proteeae), show significant siderophore activity. Their iron-binding properties were confirmed by the chrome azurol S assay and UV spectra. These compounds form ligand-to-metal charge transfer bands in the range of 400 to 500 nm. Additional absorption bands of the enolized ligands at 500 to 700 nm are responsible for color formation. Siderophore activity was most pronounced with alpha-keto acids possessing an aromatic or heteroaromatic side chain, like phenylpyruvic acid and indolylpyruvic acid, resulting from deamination of phenylalanine and tryptophan, respectively. In addition, alpha-keto acids possessing longer nonpolar side chains, like alpha-ketoisocaproic acid or alpha-ketoisovaleric acid and even alpha-ketoadipic acid, also showed siderophore activity which was absent or negligible with smaller alpha-keto acids or those possessing polar functional groups, like pyruvic acid, alpha-ketobutyric acid, or alpha-ketoglutaric acid. The fact that deaminase-negative enterobacteria, like Escherichia coli and Salmonella spp., could not utilize alpha-keto acids supports the view that specific iron-carboxylate transport systems have evolved in members of the tribe Proteeae and are designed to recognize ferric complexes of both alpha-hydroxy acids and alpha-keto acids, of which the latter can easily be generated by L-amino acid deaminases in an amino acid-rich medium. Exogenous siderophores, like ferric hydroxamates (ferrichromes) and ferric polycarboxylates (rhizoferrin and citrate), were also utilized by members of the tribe Proteeae.
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PMID:Alpha-keto acids are novel siderophores in the genera Proteus, Providencia, and Morganella and are produced by amino acid deaminases. 847 34

The L-pyrrolidonyl peptidase activities of 1,033 strains of the family Enterobacteriaceae were investigated by the paper strip method to evaluate their usefulness for screening those organisms, especially Salmonella cultures. We also evaluated the usefulness of indole and tryptophan deaminase paper strip tests as supplements to the L-pyrrolidonyl peptidase test for the rapid identification of Salmonella cultures. The paper strip tests are simple, and the results are obtainable within 10 min.
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PMID:Evaluation of L-pyrrolidonyl peptidase paper strip test for differentiation of members of the family Enterobacteriaceae, particularly Salmonella spp. 878 97

We examined the taxonomic position of seven Aeromonas isolates, recovered from Flemish and Scottish drinking water production plants and reservoirs, which were previously recognized by numerical analysis of genomic AFLP fingerprints as members of an unknown Aeromonas taxon that most closely resembled the species Aeromonas bestiarum (DNA hybridization group [HG] 2). The new phenotypic and DNA-DNA hybridization data obtained in this study show that the A. bestiarum-like strains constitute a separate Aeromonas species, for which the name Aeromonas popoffii sp. nov. is being proposed. The new species exhibited an internal DNA relatedness ranging from 79 to 100% and was 22 to 63% related to the type or reference strains of other Aeromonas spp. The highest DNA binding values were determined with A. bestiarum (51 to 63%), followed by Aeromonas hydrophila sensu stricto (HG1; 50 to 60%) and Aeromonas salmonicida (HG3; 39 to 55%). Although fingerprints generated by ribotyping and cellular fatty acid analysis often were highly similar, minor differences between the respective fingerprints were of significance for the differentiation of A. popoffii from its closest taxonomic neighbors, HG1, HG2, and HG3. Phenotypically, all seven strains of A. popoffii were positive for acid and gas production from D-glucose and glycerol, growth in KCN broth, arginine dihydrolase, DNase, Voges-Proskauer reaction, and resistance to vibriostatic agent O/129 and ampicillin but displayed negative reactions for production of urease, tryptophan deaminase, ornithine decarboxylase, and lysine decarboxylase (LDC). None of the strains displayed strong hemolytic activity. The lack of D-sucrose fermentation and LDC production and the ability to utilize DL-lactate as the sole energy and carbon source were useful characteristics for the biochemical separation of A. popoffii from A. bestiarum. Other Aeromonas spp. could be differentiated phenotypically from the new species by at least two features. The chromosomal G+C content of A. popoffii ranges from 57.7 to 59.6 mol%. Strain LMG 17541 is proposed as the type strain.
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PMID:Aeromonas popoffii sp. nov., a mesophilic bacterium isolated from drinking water production plants and reservoirs. 933 24

Four types of hepatic porphyria (acute intermittent porphyria; hereditary coprophorphyria; variegate porphyria; delta-aminolevulinate dehydratase deficiency porphyria) present clinically with an identical neurological syndrome. Symptoms include severe abdominal pain, vomiting, constipation, hypertension, tachycardia, and bladder dysfunction. These symptoms have been ascribed to autonomic neuropathy. Other symptoms are motor weakness and sensory involvement, which correlate with peripheral axonal neuropathy, and mental symptoms occurring without clear morphological findings in the cerebrum. The pathogenetic mechanisms which lead to the neurological dysfunction have remained poorly understood, partly due to the lack of a suitable animal model of these rare disorders. Two hypotheses, the possible neurotoxicity of delta-aminolevulinate (ALA) and heme deficiency in nervous tissue are discussed and corresponding data from porphobilinogen-deaminase deficient mice are presented. The present evidence suggests that multiple mechanisms interact in causing the varied symptoms, including ALA interaction with GABA receptors, altered tryptophan metabolism, and possibly heme depletion in nerve cells.
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PMID:Acute porphyrias: pathogenesis of neurological manifestations. 951 77

The involvement of tyrosine residues in the allosteric function of the enzyme glucosamine 6-phosphate deaminase from Escherichia coli was first proposed on the basis of a theoretical analysis of the sequence and demonstrated by spectrophotometric experiments. Two tyrosine residues, Tyr121 and Tyr254, were indicated as involved in the mechanism of cooperativity and in the allosteric regulation of the enzyme [Altamirano et al. (1994) Eur. J. Biochem. 220, 409-413]. Tyr121 replacement by threonine or tryptophan altered the symmetric character of the T --> R transition [Altamirano et al. (1995) Biochemistry 34, 6074-6082]. From crystallographic data of the R allosteric conformer, Tyr254 has been shown to be part of the allosteric pocket [Oliva et al. (1995) Structure 3, 1323-1332]. Although it is not directly involved in binding the allosteric activator, N-acetylglucosamine 6-phosphate, Tyr 254 is hydrogen bonded through its phenolic hydroxyl to the backbone carbonyl from residue 161 in the neighboring polypeptide chain. Kinetic and binding experiments with the mutant form Tyr254-Phe of the enzyme reveal that this replacement caused an uncoupling of the homotropic and heterotropic effects. Homotropic cooperativity diminished and the allosteric activation pattern changed from one of the K-type in the wild-type deaminase to a mixed K-V pattern. On the other hand, Tyr254-Trp deaminase is kinetically closer to a K-type enzyme and it has a higher catalytic efficiency than the wild-type protein. These results show that the interactions of Tyr254 are fundamental in coupling binding in the active site to events occurring in the allosteric pocket of E. coli glucosamine 6-P deaminase.
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PMID:Tyr254 hydroxyl group acts as a two-way switch mechanism in the coupling of heterotropic and homotropic effects in Escherichia coli glucosamine-6-phosphate deaminase. 960 Oct 45

Proteins induced by acid or base, during long-term aerobic or anaerobic growth in complex medium, were identified in Escherichia coli. Two-dimensional gel electrophoresis revealed pH-dependent induction of 18 proteins, nine of which were identified by N-terminal sequencing. At pH 9, tryptophan deaminase (TnaA) was induced to a high level, becoming one of the most abundant proteins observed. TnaA may reverse alkalinization by metabolizing amino acids to produce acidic products. Also induced at high pH, but only in anaerobiosis, was glutamate decarboxylase (GadA). The gad system (GadA/GadBC) neutralizes acidity and enhances survival in extreme acid; its induction during anaerobic growth may help protect alkaline-grown cells from the acidification resulting from anaerobic fermentation. To investigate possible responses to internal acidification, cultures were grown in propionate, a membrane-permeant weak acid which acidifies the cytoplasm. YfiD, a homologue of pyruvate formate lyase, was induced to high levels at pH 4.4 and induced twofold more by propionate at pH 6; both of these conditions cause internal acidification. At neutral or alkaline pH, YfiD was virtually absent. YfiD is therefore a strong candidate for response to internal acidification. Acid or propionate also increased the expression of alkyl hydroperoxide reductase (AhpC) but only during aerobic growth. At neutral or high pH, AhpC showed no significant difference between aerobic and anaerobic growth. The increase of AhpC in acid may help protect the cell from the greater concentrations of oxidizing intermediates at low pH. Isocitrate lyase (AceA) was induced by oxygen across the pH range but showed substantially greater induction in acid or in base than at pH 7. Additional responses observed included the induction of MalE at high pH and induction of several enzymes of sugar metabolism at low pH: the phosphotransferase system components ManX and PtsH and the galactitol fermentation enzyme GatY. Overall, our results indicate complex relationships between pH and oxygen and a novel permeant acid-inducible gene, YfiD.
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PMID:Acid- and base-induced proteins during aerobic and anaerobic growth of Escherichia coli revealed by two-dimensional gel electrophoresis. 1009

An L-N-carbamoyl amino acid amidohydrolase (L-N-carbamoylase) from Arthrobacter aurescens DSM 3747 was cloned in E. coli and the nucleotide sequence was determined. After expression of the gene in E. coli the enzyme was purified to homogeneity and characterized. The enzyme was shown to be strictly L-specific and exhibited the highest activity in the hydrolysis of beta-aryl substituted N alpha-carbamoyl-alanines as e.g. N-carbamoyl-tryptophan. Carbamoyl derivatives of beta-alanine and charged aliphatic amino acids were not accepted as substrates. The N-carbamoylase of A. aurescens DSM 3747 differs from all known enzymes with respect to its substrate specificity although amino acid sequence identity scores of 35-38% to other N-carbamoylases have been detected. The enzyme consists of two subunits of 44,000 Da, and has an isoelectric point of 4.3. The optima of temperature and pH were determined to be 50 degrees C and pH 8.5 respectively. At 37 degrees C the enzyme was completely stable for several days.
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PMID:Cloning, nucleotide sequence and expression of a new L-N-carbamoylase gene from Arthrobacter aurescens DSM 3747 in E. coli. 1019 52


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