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)

Saccharomyces cerevisiae produces two L-asparaginases (ASPs), intracellular ASP I and cell-wall ASP II. In this report, the ASP-I-encoding gene, ASP1, has been identified by homology cloning based on the structures of ASPs from other organisms. Its deduced protein product has a subunit M(r) of 41,414, and shows substantial sequence homology to the bacterial amidohydrolase family. The product of the S. cerevisiae ASP3 gene, a further member of this family, encoding the nitrogen catabolite-regulated cell-wall ASP II, has 46% overall sequence identity to ASP1. Duplication of ancestral asparaginase genes, resulting in separate intra- and extracellular isozymes, appears to have occurred independently in the prokaryotic and eukaryotic lineages. Exact physical mapping of the new cloned ASP1 gene locates it 73% of the distance from the left telomere of chromosome IV, at a position precisely matching the known genetic map location of ASP1. This, along with the structural features of the clone, confirms that ASP1 is the structural gene encoding cytoplasmic ASP I in S. cerevisiae. Sequence analysis of the ethylmethanesulfonate-induced asp1-12 allele of strain XE101-1A revealed a C-->T transition altering Ala176 to Val. This residue lies within a highly conserved region, and the results suggests a critical function for Ala176 in ASP function. Expression of ASP1 and other recombinant ASPs may allow access to improved products for use in the chemotherapy of leukaemia.
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PMID:The ASP1 gene of Saccharomyces cerevisiae, encoding the intracellular isozyme of L-asparaginase. 802 56

Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources through the nitrate assimilatory pathway. The structural genes for assimilatory nitrate and nitrite reductases together with genes necessary for nitrate transport form an operon, nasFEDCBA. Expression of the nasF operon is regulated both by general nitrogen control and also by nitrate or nitrite induction. We have identified a gene, nasR, that is necessary for nitrate and nitrite induction. The nasR gene, located immediately upstream of the nasFEDCBA operon, encodes a 44-kDa protein. The NasR protein shares carboxyl-terminal sequence similarity with the AmiR protein of Pseudomonas aeruginosa, the positive regulator of amiE (aliphatic amidase) gene expression. In addition, we present evidence that the nasF operon is not autogenously regulated.
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PMID:Identification and structure of the nasR gene encoding a nitrate- and nitrite-responsive positive regulator of nasFEDCBA (nitrate assimilation) operon expression in Klebsiella pneumoniae M5al. 805 Oct 20

Two bacterial isolates capable of utilizing acrylamide as the sole source of carbon and nitrogen were isolated from herbicide-contaminated soil samples and identified as Pseudomonas sp. and Xanthomonas maltophilia. Batch cultures of Pseudomonas sp. and X. maltophilia completely degraded 62.8 mM acrylamide to acrylic acid and ammonia in 24 and 48 h, respectively. Pseudomonas sp. and X. maltophilia, when immobilized in calcium alginate, markedly increased the rate of degradation of acrylamide over batch cultures. Cells of the isolates immobilized in calcium alginate degraded acrylamide to acrylic acid and ammonia in less than 6 h. Initial metabolism of acrylamide by immobilized cells of Pseudomonas sp. followed by inoculation with nonimmobilized cells after 6 h totally removed acrylamide and its metabolites in 72 h. A similar procedure with X. maltophilia resulted in the total metabolism of acrylamide in 96 h. An inducible, intracellular amidase was responsible for the hydrolysis of acrylamide to acrylic acid and ammonia. The specific activity of Pseudomonas sp. amidase was higher than the specific activity of X. maltophilia amidase.
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PMID:Degradation of acrylamide by immobilized cells of a Pseudomonas sp. and Xanthomonas maltophilia. 846 21

The isolation of mutants defective in adenine metabolism in Bacillus subtilis has provided a tool that has made it possible to investigate the role of adenine deaminase in adenine metabolism in growing cells. Adenine deaminase is the only enzyme that can deaminate adenine compounds in B. subtilis, a reaction which is important for adenine utilization as a purine and also as a nitrogen source. The uptake of adenine is strictly coupled to its further metabolism. Salvaging of adenine is inhibited by the stringent response to amino acid starvation, while the deamination of adenine is not. The level of adenine deaminase was reduced when exogenous guanosine served as the purine source and when glutamine served as the nitrogen source. The enzyme level was essentially the same whether ammonia or purines served as the nitrogen source. Reduced levels were seen on poor carbon sources. The ade gene was cloned, and the nucleotide sequence and mRNA analyses revealed a single-gene operon encoding a 65-kDa protein. By transductional crosses, we have located the ade gene to 130 degrees on the chromosomal map.
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PMID:Role of adenine deaminase in purine salvage and nitrogen metabolism and characterization of the ade gene in Bacillus subtilis. 855 May 22

Escherichia coli asparagine synthetase B (AS-B) catalyzes the synthesis of asparagine from aspartic acid and glutamine in an ATP-dependent reaction. The ability of this enzyme to employ hydroxylamine and L-glutamic acid gamma-monohydroxamate (LGH) as alternative substrates in place of ammonia and L-glutamine, respectively, has been investigated. The enzyme is able to function as an amidohydrolase, liberating hydroxylamine from LGH with high catalytic efficiency, as measured by k(cat)/K(M). In addition, the kinetic parameters determined for hydroxylamine in AS-B synthetase activity are very similar to those of ammonia. Nitrogen transfer from LGH to yield aspartic acid beta-monohydroxamate is also catalyzed by AS-B. While such an observation has been made for a few members of the trpG amidotransferase family, our results appear to be the first demonstration that nitrogen transfer can occur from glutamine analogs in a purF amidotransferase. However, k(cat)/K(M) for the ATP-dependent transfer of hydroxylamine from LGH to aspartic acid is reduced 3-fold relative to that for glutamine-dependent asparagine synthesis. Further, the AS-B mutant in which asparagine is replaced by alanine (N74A) can also use hydroxylamine as an alternate substrate to ammonia and catalyze the hydrolysis of LGH. The catalytic efficiencies (k(cat)/K(M)) of nitrogen transfer from LGH and L-glutamine to beta-aspartyl-AMP are almost identical for the N74A AS-B mutant. These observations support the proposal that Asn-74 plays a role in catalyzing glutamine-dependent nitrogen transfer. We interpret our kinetic data as further evidence against ammonia-mediated nitrogen transfer from glutamine in the purF amidotransferase AS-B. These results are consistent with two alternate chemical mechanisms that have been proposed for this reaction [Boehlein, S. K., Richards, N. G. J., Walworth, E. S., & Schuster, S. M. (1994) J. Biol. Chem. 269, 26789-26795].
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PMID:Glutamic acid gamma-monohydroxamate and hydroxylamine are alternate substrates for Escherichia coli asparagine synthetase B. 860 42

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

The CHA1 gene of Saccharomyces cerevisiae encodes the catabolic L-serine (L-threonine) deaminase responsible for the utilization of serine/threonine as nitrogen sources. Previously, we identified two serine/threonine response elements in the CHA1 promoter, UASCHA. We report isolation of a mutation, cha4-1, that impairs serine/threonine induction of CHA1 transcription. The cha4-1 allele causes noninducibility of a CHA1 p-lacZ translational gene fusion, indicating that Cha4p exerts its action through the CHA1 promoter. Molecular and genetic mapping positioned the cha4 locus 17 cM centromere proximal to put1 on chromosome XII. The coding region of CHA4 predicts a 648-amino acid protein with a DNA-binding motif (residues 43-70) belonging to the Cys6 zinc cluster class. Gel retardation employing a recombinant peptide, Cha4p1-174, demonstrated that the peptide in vitro specifically binds UASCHA. Binding is abolished by a G-C to T-A mutation in the middle bases of the two CEZ-elements in UASCHA. The transcriptional activating ability of UASCHA derivatives in vivo correlates with their ability to bind Cha4p1-174 in vitro. We conclude that Cha4p is a positive regulator of CHA1 transcription and that Cha4p alone, or as part of a complex, is binding UASCHA.
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PMID:Cha4p of Saccharomyces cerevisiae activates transcription via serine/threonine response elements. 888 13

Deamination or oxidative cleavage of the carbon-nitrogen bond in various phenylisopropylamines was examined in liver microsomes from rabbits and rats, and in reconstituted systems containing CYP2C subfamily isozymes. Kinetic studies of phenylacetone formation from six amphetamine (AP) derivatives, catalyzed by rabbit liver microsomes, indicated that AP had the highest apparent affinity (lowest K(m)) and increasing the size of the substituent on the nitrogen atom decreased the affinity. The values of maximal velocity increased with increasing size of the substituent. Experiments with purified CYP2C3 from rabbit liver gave similar results: this enzyme showed the highest activity for phenylacetone formation from benzphetamine (BZP) and showed lower activities with compounds having smaller nitrogen substituents. Based on these results, we conclude that among a series of AP derivatives, the parent phenylisopropylamine has the highest affinity for rabbit liver deaminase, where as BZP has the highest turnover. However, the intrinsic clearance (Vmax/K(m)) values for the individual reactions tended to be comparable. The rates of BZP and deprenyl N-demethylation by rat CYP2C11 and 2C13 were far greater than those of the reactions at other N-alpha-positions. This result indicated that rat CYP2C enzymes have a more rigid regioselectivity than rabbit CYP2C3 for the deamination/N-dealkylation of phenylisopropylamines.
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PMID:Deamination of amphetamines by cytochromes P450: studies on substrate specificity and regioselectivity with microsomes and purified CYP2C subfamily isozymes. 907 58

For the production of D-amino acids, thermotolerant bacteria producing N-carbamyl-D-amino acid amidohydrolase were isolated from soil by enrichment culture at 45 degrees C with N-carbamyl-D-amino acids as the sole nitrogen source. The enzyme activities and substrate specificities of these strains were examined by the resting cells reaction. One of the enzymes, produced by Pseudomonas sp. strain KNK003A, was purified and characterized, and the amino acids of its N-terminal region were sequenced. A DNA fragment containing the gene for a thermostable N-carbamyl-D-amino acid amidohydrolase was then cloned into Escherichia coli. The gene encoded a peptide of 312 amino acids, with a calculated molecular weight of 35,000. The similarity of the deduced amino acid sequences of this enzyme and a related enzyme from a mesophile, Agrobacterium sp. strain KNK712, was 60%. A database was searched for similar sequences.
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PMID:Screening, characterization, and cloning of the gene for N-carbamyl-D-amino acid amidohydrolase from thermotolerant soil bacteria. 964 18

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


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