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)

Simultaneous HPLC determination of bromoxynil, ioxynil and dichlobenil, three arylnitrile herbicides, and their metabolic products in soil extracts and microbiological media is described. Limits of detection (LODs) ranged from 0.56 to 3.97 ppb. Slight modification of the mobile phase composition allowed determination of 13 other aromatic nitriles. Assay of aromatic nitrile hydratase, amidase or nitrilase activities is possible by the method developed.
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PMID:High-performance liquid chromatographic study of the aromatic nitrile metabolism in soil bacteria. 879 29

A peptide nitrile hydratase activity has been engineered into the cysteine protease papain by a single carefully selected mutation at the active site of the enzyme. The papain variant Gln19Glu hydrolyzes the substrate MeOCO-PheAla-CN to the corresponding amide with a kcat/KM value of 1.15 x 10(3) M-1 s-1. The reaction leads to an accumulation of the corresponding amide, which is then further hydrolyzed to the acid by the natural amidase activity of the enzyme. The pH-dependency of the nitrile hydratase activity of Gln19Glu supports the involvement of the acid form of the Glu19 residue in the reaction. The wild type enzyme displays very weak nitrile hydratase activity, and the introduction of a glutamic acid residue in the oxyanion hole of papain causes the kcat at pH 5 to increase by a factor of at least 4 x 10(5). Peptide nitriles react with cysteine proteases to form thioimidates, and the role of the glutamic acid residue introduced at position 19 in the Gln19Glu enzyme is to participate in the acid-catalyzed hydrolysis of the thiomidate to the amide by the provision of a proton to form the more reactive protonated thioimidate. This dramatically decreases the energy barrier for the hydrolysis of the thioimidate, as shown by the impressive increase in kcat. The success of the rational approach undertaken is a consequence of the level of understanding of the basic catalytic properties of cysteine proteases of the papain family.
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PMID:Engineering nitrile hydratase activity into a cysteine protease by a single mutation. 884 64

A variant of a yeast strain identified as Candida famata isolated from gold mine effluent was able to grow on acetonitrile, acrylonitrile, butyronitrile, isobutyronitrile, methacrylnitrile, propionitrile, succinonitrile, valeronitrile, acetamide, isobutyamide, and succinamide as sole nitrogen source, after acclimatization. The yeast grew on acetonitrile and acetamide at concentrations up to 4%. The utilisation of acetonitrile and acetamide by the C. famata strain probably involves hydrolysis in a two-step reaction mediated by both inducible and intracellular nitrile hydratase and amidase.
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PMID:Utilization of acetonitrile and other aliphatic nitriles by a Candida famata strain. 887 Feb 54

Cobalt is an essential component of a low molecular-mass nitrile hydratase (L-NHase) from Rhodococcus rhodochrous J1. We have found a new gene, nhlF, in the DNA region sandwiched between nhlBA encoding L-NHase and amdA encoding amidase, which are involved in the degradation of nitriles. The product of nhlF, NhlF, shows a significant sequence similarity with those of hoxN from Alcaligenes eutrophus, hupN from Bradyrhizobium japonicum, nixA from Helicobacter pylori, and ureH from Bacillus sp., which are considered to be involved in nickel uptake into these cells. Sequence and hydropathy plot analyses have shown that NhlF encodes a 352-amino acid (aa) protein with eight hydrophobic putative membrane-spanning domains. nhlF expression in R. rhodochrous ATCC 12674 and Escherichia coli JM109 confers uptake of 57Co in their cells, but not of 63Ni. The expression of both nhlF and nhlBA in R. rhodochrous ATCC 12674 exhibited higher NHase activity than nhlBA expression. These findings together with the inhibitory effect by uncouplers (CCCP and SF6847) for the cobalt uptake suggest that NhlF mediates the cobalt transport into the cell energy-dependently finally to provide L-NHase.
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PMID:A novel transporter involved in cobalt uptake. 899 Jan 57

The ability of the nitrile hydratase/amidase system from Brevibacterium R312 to biotransform tert-butylacetonitrile was studied with a view to their utilisation in the production of novel amino acids from isostructural compounds. Brevibacterium R312 was able to transform nitriles with this structure; however, the wide spectrum amidase from this organism was unable to biotransform the corresponding amide to the carboxylic acid.
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PMID:The biotransformation of t-butylacetonitrile and its boron-containing analogue trimethylamine-cyanoborane by Brevibacterium R312. 923 9

Thiocyanate hydrolase is a newly found enzyme from Thiobacillus thioparus THI 115 that converts thiocyanate to carbonyl sulfide and ammonia (Y. Katayama, Y. Narahara, Y. Inoue, F. Amano, T. Kanagawa, and H. Kuraishi, J. Biol. Chem. 267:9170-9175, 1992). We have cloned and sequenced the scn genes that encode the three subunits of the enzyme. The scnB, scnA, and scnC genes, arrayed in this order, contained open reading frames encoding sequences of 157, 126, and 243 amino acid residues, respectively, for the beta, alpha, and gamma subunits, respectively. Each open reading frame was preceded by a typical Shine-Dalgarno sequence. The deduced amino-terminal peptide sequences for the three subunits were in fair agreement with the chemically determined sequences. The protein molecular mass calculated for each subunit was compatible with that determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. From a computer analysis, thiocyanate hydrolase showed significant homologies to bacterial nitrile hydratases known to convert nitrile to the corresponding amide, which is further hydrolyzed by amidase to form acid and ammonia. The two enzymes were homologous over regions corresponding to almost the entire coding regions of the genes: the beta and alpha subunits of thiocyanate hydrolase were homologous to the amino- and carboxyl-terminal halves of the beta subunit of nitrile hydratase, and the gamma subunit of thiocyanate hydrolase was homologous to the alpha subunit of nitrile hydratase. Comparisons of the catalytic properties of the two homologous enzymes support the model for the reaction steps of thiocyanate hydrolase that was previously presented on the basis of biochemical analyses.
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PMID:Cloning of genes coding for the three subunits of thiocyanate hydrolase of Thiobacillus thioparus THI 115 and their evolutionary relationships to nitrile hydratase. 957 40

High-molecular-mass nitrile hydratase (H-NHase, 530 kDa) is a cobalt-containing enzyme produced by Rhodococcus rhodochrous J1. For efficient production of H-NHase in R. rhodochrous ATCC12674, several plasmids were constructed. The enzyme was produced in the recombinant Rhodococcus cells only in the presence of an upstream region (approximately 4 kb) of the H-NHase gene under the control of the promoter for the amidase-NHase gene cluster from Rhodococcus sp. N-774. Although H-NHase was produced as a soluble protein in the cells, the protein did not show NHase activity. However, when the recombinant R. rhodochrous ATCC12674 cells were cultured in the presence of amide compounds, such as crotonamide and methacrylamide, markedly high NHase activity was detected, Gel-filtration chromatography revealed that the NHases produced by the cells grown in the presence and absence of the amide compounds had a molecular mass of more than 500 kDa and 50-80 kDa respectively. These results suggest that the amide compounds are essential for subunit assembly to form an enzymatically active multimer. By the use of the recombinant expression system, NHase activity 1.7 times higher than that of the original strain, R. rhodochrous J1, was achieved.
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PMID:Overexpression of high-molecular-mass nitrile hydratase from Rhodococcus rhodochrous J1 in recombinant Rhodococcus cells. 965 Feb 55

A bacterial strain capable of utilizing E-pyridine-3-aldoxime as a nitrogen source was isolated from soil after a 4-month acclimation period and was identified as Rhodococcus sp. The strain contained a novel aldoxime dehydration activity that catalyzed a stoichiometric dehydration of E-pyridine-3-aldoxime to form 3-cyanopyridine. The enzyme activity was induced by various aldoximes and nitriles. The strain metabolized the aldoxime as follows: E-pyridine-3-aldoxime was dehydrated to form 3-cyanopyridine, which was converted to nicotinamide by a nitrile hydratase, and the nicotinamide was successively hydrolyzed to nicotinic acid by an amidase.
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PMID:Isolation and characterization of a bacterium possessing a novel aldoxime-dehydration activity and nitrile-degrading enzymes. 968 44

Mesophilic nitrile-degrading enzymes are widely dispersed in the Bacteria and lower orders of the eukaryotic kingdom. Two distinct enzyme systems, a nitrilase catalyzing the direct conversion of nitriles to carboxylic acids and separate but cotranscribed nitrile hydratase and amidase activities, are now well known. Nitrile hydratases are metalloenzymes, incorporating FeIII or CoII ions in thiolate ligand networks where they function as Lewis acids. In comparison, nitrilases are thiol-enzymes and the two enzyme groups have little or no apparent sequence or structural homology. The hydratases typically exist as alpha beta dimers or tetramers in which the alpha- and beta-subunits are similar in size but otherwise unrelated. Nitrilases however, are usually found as homomultimers with as many as 16 subunits. Until recently, the two nitrile-degrading enzyme classes were clearly separated by functional differences, the nitrile hydratases being aliphatic substrate specific and lacking stereoselectivity, whereas the nitrilases are enantioselective and aromatic substrate specific. The recent discovery of novel enzymes in both classes (including thermophilic representatives) has blurred these functional distinctions. Purified mesophilic nitrile-degrading enzymes are typically thermolabile in buffered solution, rarely withstanding exposure to temperatures above 50 degrees C without rapid inactivation. However, operational thermostability is often increased by addition of aliphatic acids or by use of immobilized whole cells. Low molecular stability has frequently been cited as a reason for the limited industrial application of "nitrilases"; such statements notwithstanding, these enzymes have been successfully applied for more than a decade to the kiloton production of acrylamide and more recently to the smaller-scale production of nicotinic acid, R-(-)-mandelic acid and S-(+)-ibuprofen. There is also a rapidly growing catalog of other potentially useful conversions of complex nitriles in which the regioselectivity of the enzyme coupled with the ability to achieve high conversion efficiencies without detriment to other sensitive functionalities is a distinct process advantage.
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PMID:Biochemistry and biotechnology of mesophilic and thermophilic nitrile metabolizing enzymes. 978 67

Amidases are a class of enzymes which convert amides to acids and have potential value in the development of commercial bioprocesses for the production of useful chemicals. A gene encoding an amidase in Pseudomonas putida 5B has been cloned, sequenced, and overexpressed in Escherichia coli. An additional open reading frame (P38K) encoding a putative protein of 38 kDa was found immediately upstream of the amidase gene. This work continues our characterization of a P. putida operon, which now appears to include P38K, amidase, and a stereo-specific nitrile hydratase. This characterization underlies continuing efforts in biocatalyst development.
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PMID:Cloning and nucleotide sequence of amidase gene from Pseudomonas putida. 980 53


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