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)

A mutation in a gene designated gmdA has been found to lead to loss of ability of Aspergillus nidulans to use benzamide, phenylacetamide and several other amides as sole nitrogen sources for growth. The gmdA1 lesion results in low levels of an enzyme, called the general amidase, which has acitivity for a wide range of amide substrates. This enzyme is reressed by certain nitrogen-containing metabolites, including ammonium, but is probably not regulated by induction or by carbon catabolite repression. Evidence is presented for the general amidase being distinct from the previously characterized acetamidase and formamidase enzymes. The data also indicate that there is a fourth amidase capable of the hydrolysis of valeramide and hexanamide.
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PMID:Amide utilization in Aspergillus nidulans: evidence for a third amidase enzyme. 110 71

A strain of Klebsiella pneumoniae that used aliphatic nitriles as the sole source of nitrogen was adapted to benzonitrile as the sole source of carbon and nitrogen. Gas chromatographic and mass spectral analyses of culture filtrates indicated that K. pneumoniae metabolized 8.4 mM benzonitrile to 4.0 mM benzoic acid and 2.7 mM ammonia. In addition, butyronitrile was metabolized to butyramide and ammonia. The isolate also degraded mixtures of benzonitrile and aliphatic nitriles. Cell extracts contained nitrile hydratase and amidase activities. The enzyme activities were higher with butyronitrile and butyramide than with benzonitrile and benzamide, and amidase activities were twofold higher than nitrile hydratase activities. K. pneumoniae appears promising for the bioremediation of sites contaminated with aliphatic and aromatic nitriles.
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PMID:Metabolism of benzonitrile and butyronitrile by Klebsiella pneumoniae. 153 79

In mice, the diethylglycineamide analogue of LY201116, DEGA (N-(2,6-dimethylphenyl)-4-[[(diethylamino)acetyl]amino]benzamide), is metabolized by consecutive N-deethylations for form MEGA and GA; the monoethylglycineamide and glycineamide analogues of LY201116, respectively. All of these compounds are in turn hydrolyzed to form LY201116 [4-amino-N-(2,6-dimethylphenyl)benzamide]. LY201116 is N-acetylated to form the N-acetyl metabolite, NAC. NAC is also deacetylated to reform LY201116. All of the above compounds inhibit maximal electroshock-induced seizures (MES) in mice. After oral administration, the potencies of these compounds were similar at their time of peak anticonvulsant effect. However, the MES ED50 values for the above compounds 5 min after iv dosing were 43, 13, 2, and 0.5 mg/kg for DEGA, MEGA, GA, and LY201116, respectively. Similar plasma levels of LY201116 were produced in mice 5 min after iv dosing with the respective ED50 values of the above compounds, which suggested that all of the compounds produced their anticonvulsant effects via LY201116. The in vivo metabolism of DEGA and MEGA but not GA to LY201116 was inhibited by the acylamidase inhibitor bis-(p-nitrophenyl) phosphate (BNPP). Mice predosed with BNPP were not protected by DEGA and MEGA from MES-induced seizures and the plasma samples contained little or no LY201116. The metabolism of GA to LY201116 was not inhibited by BNPP, and GA was an active anticonvulsant in BNPP-pretreated mice. The apparent iv potency of DEGA increased dramatically with time after dosing, again suggesting time-dependent, metabolically mediated liberation of the more potent anticonvulsant LY201116.
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PMID:Metabolism of the prodrug DEGA (N-(2,6-dimethylphenyl)-4-[[(diethylamino)acetyl]amino]benzamide) to the potent anticonvulsant LY201116 in mice. Effect of bis-(p-nitrophenyl)phosphate. 290 94

1. The action of the penicillin acylase enzyme of Escherichia coli N.C.I.B. 8743 on non-penicillin substrates suggests that the enzyme is an amidohydrolase. 2. The rates of hydrolysis for a small group of penicillins closely parallel those for a corresponding series of N-acylglycines. 3. For a series of E. coli strains, ability to cause rapid hydrolysis of phenylacetylglycine is correlated with ability to hydrolyse benzylpenicillin. 4. Amides and N-acylglycines are hydrolysed to the corresponding acids. The phenylacetyl group is hydrolysed most readily. Benzamide and beta-phenylpropionamide are not substrates. In a series of aliphatic acylglycines only valeryl- and hexanoyl-glycine are substrates. 5. Acylated l- but not d-alpha-amino acids are hydrolysed. d-alpha-Hydroxyphenylacetamide is a better substrate than the l compound.
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PMID:Deacylation of acylamino compounds other than penicillins by the cell-bound penicillin acylase of Escherichia coli. 490 24

The cloned 9.4-kb insert of plasmid pNHJ20L containing low-molecular-mass nitrile hydratase (L-NHase) gene from Rhodococcus rhodochrous J1 [Kobayashi, M. et al. (1991) Biochim. Biophys. Acta 1129, 23-33] was digested with various restriction enzymes, and the trimmed fragments were inserted into pUC18 or pUC19. A 1.96-kb EcoRI-SphI region located 1.9-kb downstream of the L-NHase gene was found to be essential for the expression of amidase activity in Escherichia coli; the gene arrangement of the amidase and the NHase in R. rhodochrous J1 differed from those in Rhodococcus species including N-774 and Pseudomonas chlororaphis B23. The nucleotide-determined sequence indicated that the amidase consists of 515 amino acids (54626 Da) and the deduced amino acid sequence of the amidase had high similarity to those of amidases from Rhodococcus species including N-774 and P. chlororaphis B23 and to indole-3-acetamide hydrolase from Pseudomonas savastanoi. The amidase gene modified in the nucleotide sequence upstream from its start codon expressed 8% of the total soluble protein in E. coli under the control of lac promoter. The level of amidase activity in cell-free extracts of E. coli was 0.468 unit/mg using benzamide as a substrate. This amidase was purified to homogeneity from extracts of the E. coli transformant with 30.4% overall recovery. The molecular mass of the enzyme estimated by HPLC was about 110 kDa and the enzyme consists of two subunits identical in molecular mass (55 kDa). The enzyme acted upon aliphatic amides such as propionamide and also upon aromatic amides such as benzamide. The apparent Km values for propionamide and benzamide were 0.48 mM and 0.15 mM, respectively. This amidase was highly specific for the S-enantiomer of 2-phenylpropionamide, but could not recognize the configuration of 2-chloropropionamide. It also catalyzed the transfer of an acyl group from an amide to hydroxylamine to produce the corresponding hydroxamate.
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PMID:Amidase coupled with low-molecular-mass nitrile hydratase from Rhodococcus rhodochrous J1. Sequencing and expression of the gene and purification and characterization of the gene product. 791 90

The enantioselective amidase from Rhodococcus sp. strain R312 was produced in Escherichia coli and was purified in one chromatographic step. This enzyme was shown to catalyze the acyl transfer reaction to hydroxylamine from a wide range of amides. The optimum working pH values were 7 with neutral amides and 8 with alpha-aminoamides. The reaction occurred according to a Ping Pong Bi Bi mechanism. The kinetic constants demonstrated that the presence of a hydrophobic moiety in the carbon side chain considerably decreased the Km(amide) values (e.g., Km(amide) = 0.1 mM for butyramide, isobutyramide, valeramide, pivalamide, hexanoamide, and benzamide). Moreover, very high turnover numbers (kcat) were obtained with linear aliphatic amides (e.g., kcat = 333 s-1 with hexanoamide), whereas branched-side-chain-, aromatic cycle- or heterocycle-containing amides were sterically hindered. Carboxylic acids, alpha-amino acids, and methyl esters were not acyl donors or were very bad acyl donors. Only amides and hydroxamic acids, both of which contained amide bonds, were determined to be efficient acyl donors. On the other hand, the highest affinities of the acyl-enzyme complexes for hydroxylamine were obtained with short, polar or unsaturated amides as acyl donors (e.g., KmNH2OH = 20, 25, and 5 mM for acetyl-, alanyl-, and acryloyl-enzyme complexes, respectively). No acyl acceptors except water and hydroxylamine were found. Finally, the purified amidase was shown to be L-enantioselective towards alpha-hydroxy- and alpha-aminoamides.
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PMID:Acyl transfer activity of an amidase from Rhodococcus sp. strain R312: formation of a wide range of hydroxamic acids. 968 39

The amidase from Rhodococcus rhodochrous J1, which hydrolyzes an amide to an acid and ammonium, was surprisingly found to catalyze the hydrolytic cleavage of the C-N triple bond in a nitrile to form an acid and ammonium stoichiometrically. The amidase exhibited a Km of 3.26 mM for benzonitrile in contrast to that of 0.15 mM for benzamide as the original substrate, but the Vmax for benzonitrile was about 116000 of that for benzamide. A mutant amidase containing alanine instead of Ser195, which is essential for amidase catalytic activity, showed no nitrilase activity, demonstrating that this residue plays a crucial role in the hydrolysis of nitriles as well as amides.
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PMID:The catalytic mechanism of amidase also involves nitrile hydrolysis. 984 47

While amides were reported to be completely inert as substrates for all nitrilases reported to date, the nitrilase from Rhodococcus rhodochrous J1, which catalyzes the hydrolytic cleavage of the C-N triple bond in nitrile to form acid and ammonium, was surprisingly found to catalyze hydrolysis of amide to acid and ammonium stoichiometrically. This nitrilase exhibited a Km of 2.94 mM for benzamide, similar to that for benzonitrile as the original substrate (2.10 mM), but the Vmax for benzamide was six orders of magnitude lower than that for benzonitrile. Benzamide inhibited the nitrilase reaction in a reversible, apparently competitive manner. A mutant nitrilase containing alanine or serine instead of Cys165, which is essential for nitrilase catalytic activity, showed no amidase activity. This observation demonstrated that Cys165 plays a crucial role in the hydrolysis of amides as well as nitriles. Together with some reports that certain nitrilases were previously noted to produce low amounts of amide as a by-product from nitrile, the above unexpected findings suggested the existence of a common tetrahedral intermediate in the nitrilase reaction involving nitrile or amide as a substrate.
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PMID:Nitrilase catalyzes amide hydrolysis as well as nitrile hydrolysis. 991 84

A pyrazinamidase (PZase)-deficient pncA mutant of Mycobacterium tuberculosis, constructed by allelic exchange, was used to investigate the effects of heterologous amidase gene expression on the susceptibility of this organism to pyrazinamide (PZA) and related amides. The mutant was highly resistant to PZA (MIC, >2,000 microg/ml), in accordance with the well-established role of pncA in the PZA susceptibility of M. tuberculosis (A. Scorpio and Y. Zhang, Nat. Med. 2:662-667, 1996). Integration of the pzaA gene encoding the major PZase/nicotinamidase from Mycobacterium smegmatis (H. I. M. Boshoff and V. Mizrahi, J. Bacteriol. 180:5809-5814, 1998) or the M. tuberculosis pncA gene into the pncA mutant complemented its PZase/nicotinamidase defect. In both pzaA- and pncA-complemented mutant strains, the PZase activity was detected exclusively in the cytoplasm, suggesting an intracellular localization for PzaA and PncA. The pzaA-complemented strain was hypersensitive to PZA (MIC, </=10 microg/ml) and nicotinamide (MIC, >/=20 microg/ml) and was also sensitive to benzamide (MIC, 20 microg/ml), unlike the wild-type and pncA-complemented mutant strains, which were highly resistant to this amide (MIC, >500 microg/ml). This finding was consistent with the observation that benzamide is hydrolyzed by PzaA but not by PncA. Overexpression of PzaA also conferred sensitivity to PZA, nicotinamide, and benzamide on M. smegmatis (MIC, 150 microg/ml in all cases) and rendered Escherichia coli hypersensitive for growth at low pH.
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PMID:Expression of Mycobacterium smegmatis pyrazinamidase in Mycobacterium tuberculosis confers hypersensitivity to pyrazinamide and related amides. 1098 52

Two unlinked loci, gmdA and bzuA, have previously been identified as being required for the utilization of benzamide as the sole nitrogen source by Aspergillus nidulans. We have cloned each of these genes via direct complementation. The gmdA gene encodes a predicted product belonging to the amidase signature sequence family that displays similarity to AmdS from A. nidulans. However, identity is significantly higher to the amdS gene from Aspergillus niger. The bzuA gene encodes a protein belonging to the cytochrome P450 superfamily and is orthologous to the benzoate para-hydroxylase-encoding gene bphA of A. niger. The bzuA1 mutation prevents the use of benzoate as a carbon source and intracellular accumulation of benzoate results in growth inhibition on benzamide. Northern blot analysis has shown that gmdA expression is subject solely to AreA-dependent nitrogen metabolite repression while bzuA is strongly benzoate inducible and subject to CreA-mediated carbon catabolite repression and a probable inactivation of benzoate induction by glucose. Fluorescence microscopy of a fusion of the N-terminal end of BzuA to green fluorescent protein revealed that this protein localizes to the endoplasmic reticulum.
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PMID:The genes gmdA, encoding an amidase, and bzuA, encoding a cytochrome P450, are required for benzamide utilization in Aspergillus nidulans. 1184 76


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