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)

L-Vinylglycine (L-VG) has been shown to be a mechanism-based inhibitor of 1-aminocyclopropane-1-carboxylate (ACC) synthase [Satoh, S., and Yang, S. F. (1989) Plant Physiol. 91, 1036-1039] as well as of other pyridoxal phosphate-dependent enzymes. This report demonstrates that L-VG is primarily an alternative substrate for the enzyme. The L-VG deaminase activity of ACC synthase yields the products alpha-ketobutyrate and ammonia with a k(cat) value of 1.8 s(-1) and a K(m) value of 1.4 mM. The k(cat)/K(m) of 1300 M(-1) s(-1) is 0.17% that of the diffusion-controlled reaction with the preferred substrate, S-adenosyl-L-methionine. The enzyme-L-VG complex partitions to products 500 times for every inactivation event. The catalytic mechanism proceeds through a spectrophotometrically detected quinonoid with lambda(max) of 530 nm, which must rearrange to a 2-aminocrotonate aldimine to yield final products. Alternative mechanisms for the inactivation reaction are presented, and the observed kinetics for the full reaction course are satisfactorily modeled by kinetic simulation. The inactive enzyme is an aldimine with lambda(max) of 432 nm. It is resistant to NaBH(3)CN but is reduced by NaBH(4). ACC synthase is now expressed in Pichia pastoris with an improved yield of 10 mg/L.
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PMID:L-Vinylglycine is an alternative substrate as well as a mechanism-based inhibitor of 1-aminocyclopropane-1-carboxylate synthase. 1070 93

We have already described how 1-aminocyclopropane-1-carboxylic acid (ACC), which is a precursor of the plant hormone ethylene, is synthesized in Penicillium citrinum through the same reaction by the catalysis of ACC synthase [EC 4.4.1.14] as in higher plants. In addition, ACC deaminase [EC 4.1.99.4], which degrades ACC to 2-oxobutyrate and ammonia, was also purified from this strain. To study control of induction of ACC deaminase in this organism, we have isolated and analyzed the cDNA of P. citrinum ACC deaminase and studied the expression of ACC deaminase mRNA in P. citrinum cells. By the analysis of peptides from the digests of the purified and modified ACC deaminase with lysylendopeptidase, 70 % of its amino acid sequences were obtained. These amino acid sequences were used to identify a cDNA, consisting of 1,233 bp with an open reading frame of 1,080 bp encoding ACC deaminase with 360 amino acids. The deduced amino acids from the cDNA are identical by 52% and 45% to those of enzymes of Pseudomonas sp. ACP and Hansenula saturnus. Through Northern blot analysis, we found that the mRNA of ACC deaminase was expressed in P. citrinum cells grown in a medium containing 0.05% L-methionine. These findings suggest that ACC synthesized by ACC synthase and accumulated in P. citrinum intracellular spaces can induce the ACC deaminase that degrades the ACC.
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PMID:1-aminocyclopropane-1-carboxylate (ACC) deaminase induced by ACC synthesized and accumulated in Penicillium citrinum intracellular spaces. 1073 85

Enzymatic activities that could be involved in methanethiol generation in five cheese-ripening bacteria were assayed, and the major sulfur compounds produced were identified. L-Methionine and alpha-keto-gamma-methyl-thio-butyric acid demethiolating activities were detected in whole cells and cell extracts (CFEs) of all the bacteria tested. No L-methionine deaminase activity could be detected in any of the ripening bacteria and L-methionine aminotransferase was detected in CFEs of Brevibacterium linens, Micrococcus luteus, and Corynebacterium glutamicum. The results suggest that several pathways for L-methionine catabolism probably coexist in these ripening bacteria.
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PMID:Diversity of L-methionine catabolism pathways in cheese-ripening bacteria. 1109 40

Volatile sulphur compounds are major flavouring compounds in many traditional fermented foods including cheeses. These compounds are products of the catabolism of L-methionine by cheese-ripening microorganisms. The diversity of L-methionine degradation by such microorganisms, however, remains to be characterized. The objective of this work was to compare the capacities to produce volatile sulphur compounds by five yeasts, Geotrichum candidum, Yarrowia lipolytica, Kluyveromyces lactis, Debaryomyces hansenii, Saccharomyces cerevisiae and five bacteria, Brevibacterium linens, Corynebacterium glutamicum, Arthrobacter sp., Micrococcus lutens and Staphylococcus equorum of technological interest for cheese-ripening. The ability of whole cells of these microorganisms to generate volatile sulphur compounds from L-methionine was compared. The microorganisms produced a wide spectrum of sulphur compounds including methanethiol, dimethylsulfide, dimethyldisulfide, dimethyltrisulfide and also S-methylthioesters, which varied in amount and type according to strain. Most of the yeasts produced methanethiol, dimethylsulfide, dimethyldisulfide and dimethyltrisulfide but did not produce S-methylthioesters, apart from G. candidum that produced S-methyl thioacetate. Bacteria, especially Arth. sp. and Brevi. linens, produced the highest amounts and the greatest variety of volatile sulphur compounds includling methanethiol, sulfides and S-methylthioesters, e.g. S-methyl thioacetate, S-methyl thiobutyrate, S-methyl thiopropionate and S-methyl thioisovalerate. Cell-free extracts of all the yeasts and bacteria were examined for the activity of enzymes possibly involved in L-methionine catabolism, i.e. L-methionine demethiolase, L-methionine aminotransferase and L-methionine deaminase. They all possessed L-methionine demethiolase activity, while some (K. lactis, Deb. hansenii, Arth. sp., Staph. equorum) were deficient in L-methionine aminotransferase, and none produced L-methionine deaminase. The catabolism of L-methionine in these microorganisms is discussed.
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PMID:L-methionine degradation potentialities of cheese-ripening microorganisms. 1192 62

In many GL-7ACA acylases, the first Ser residue at the N-terminal of beta-subunit is the catalytic center. In order to investigate relationship between the N-terminal structure and catalytic activities, peptide replacement and site-directed mutagenesis were performed at the N-terminal of beta-subunit of GL-7ACA acylase C130. When the N-terminal 8 amino acid residues of C130 were replaced by the corresponding sequence of penicillin acylases PAC and PGA, respectively, the first mutant B8PAC lost the activity of the acylase, and the second mutant B8PGA had lower activity with the K(m) value increasing from 0.44x10(-3)mol.L(-1) to 0.55x10(-3) mol.L(-1), and the k(cat) decreasing from 4.92 s(-1) to 1.64 s(-1). Although the substitution of Trp (beta4) by Tyr did not change the K(m) value, the k (cat) decreased to 2.29 s(-1). When the Trp was substitued by Leu, both the K ( m ) and k ( cat ) values decreased. Compared with the wild type, mutations of Ser (beta3) to Met, Ala and Cys caused decrease of K(m) values by 52.27%, 43.18% and 38.64%, respectively. Mutation of Asn (beta2) to Gln caused the K ( m ) value being increased by 5-fold, and k ( cat ) decreased by 10-fold. These results suggested that the N-terminal amino acid residues of beta-subunit in GL-7ACA acylase C130 are important for enzyme function.
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PMID:Mutagenesis of N-terminal Amino Acid Residues in beta-subunit of Glutaryl-7-amino-cephalosporanic Acid Acylase C130. 1203 60

N-Carbamoyl D-amino acid amidohydrolase (D-NCAase) that catalyzes the stereospecific hydrolysis of N-carbamoyl D-amino acids to their corresponding D-amino acids is valuable in pharmaceutical industry. Agrobacterium radiobacter D-NCAase is sensitive to oxidative damage by hydrogen peroxide. To investigate the role of methionine residues in oxidative inactivation, each of the nine methionine residues in A. radiobacter D-NCAase was substituted with leucine, respectively, by site-directed mutagenesis. Except for two mutants (Met5Leu and Met31Leu) with similar activities, seven mutants (Met73Leu, Met167Leu/Met169Leu, Met184Leu, Met220Leu, Met239Leu, Met244Leu, and Met239Leu/Met244Leu) were found to have reduced activities. In the presence of H(2)O(2), three mutants (Met239Leu, Met244Leu, and Met239Leu/Met244Leu) with substitution of highly solvent-accessible methionines by leucines retained their activities. The other mutants were also considerably resistant to chemical oxidation than was the wild-type enzyme. Thus, substitution of solvent-accessible methionine residues with leucine to enhance oxidative stability of D-NCAase is practical but might be with compromised activity.
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PMID:Enhancing oxidative resistance of Agrobacterium radiobacter N-carbamoyl D-amino acid amidohydrolase by engineering solvent-accessible methionine residues. 1223 15

An N-acyl-d-amino acid amidohydrolase (N-D-AAase) was identified in cell extracts of a strain, Iso1, isolated from an environment containing N-acetyl-d-methionine. The bacterium was classified as Variovorax paradoxus by phylogenetic analysis. The gene was cloned and sequenced. The gene consisted of a 1467-bp ORF encoding a polypeptide of 488 amino acids. The V. paradoxusN-D-AAase showed significant amino acid similarity to the N-acyl-d-amino acid amidohydrolases of the two eubacteria Alcaligenes xylosoxydans A-6 (44-56% identity), Alcaligenes facelis DA1 (54% identity) and the hyperthermophilic archaeon Pyrococcus abyssi (42% identity). After over-expression of the N-D-AAase protein in Escherichia coli, the enzyme was purified by multistep chromatography. The native molecular mass was 52.8 kDa, which agreed with the predicted molecular mass of 52 798 Da and the enzyme appeared to be a monomer protein by gel-filtration chromatography. A homogenous protein with a specific activity of 516 U.mg-1 was finally obtained. After peptide sequencing by LC/MS/MS, the results were in agreement with the deduced amino acid sequence of the N-D-AAase. The pI of the enzyme was 5.12 and it had an optimal pH and temperature of 7.5 and 50 degrees C, respectively. After 30 min heat treatment at 45 degrees C, between pH 6 and pH 8, 80% activity remained. The N-D-AAase had higher hydrolysing activity against N-acetyl-d-amino acid derivates containing d-methionine, d-leucine and d-alanine and against N-chloroacetyl-d-phenylalanine. Importantly, the enzyme does not act on the N-acetyl-l-amino acid derivatives. The enzyme was inhibited by chelating agents and certain metal ions, but was activated by 1 mm of Co2+ and Mg2+. Thus, the N-D-AAase from V. paradoxus can be considered a chiral specific and metal-dependent enzyme.
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PMID:Identification and characterization of a new gene from Variovorax paradoxus Iso1 encoding N-acyl-D-amino acid amidohydrolase responsible for D-amino acid production. 1235 18

The hydrolysis of N-acetyl-L-methionine, N-acetylglycine, N-acetyl-L-phenylalanine, and N-acetyl-L-alanine at 298.35K by porcine kidney acylase I (EC 3.5.1.14) was monitored by the heat released upon mixing of the substrate and enzyme in a differential stopped flow microcalorimeter. Values for the Michaelis constant (K(m)) and the catalytic constant (k(cat)) were determined from the progress of the reaction curve employing the integrated form of the Michaelis-Menten equation for each reaction mixture. When neglecting acetate product inhibition of the acylase, values for k(cat) were up to a factor of 2.3 larger than those values determined from reciprocal initial velocity-initial substrate concentration plots for at least four different reaction mixtures. In addition, values for K(m) were observed to increase linearly with an increase in the initial substrate concentration. When an acetate product inhibition constant of 600+/-31M(-1), determined by isothermal titration calorimetry, was used in the progress curve analysis, values for K(m) and k(cat) were in closer agreement with their values determined from the reciprocal initial velocity versus initial substrate concentration plots. The reaction enthalpies, Delta(r)H(cal), which were determined from the integrated heat pulse per amount of substrate in the reaction mixture, ranged from -4.69+/-0.09kJmol(-1) for N-acetyl-L-phenylalanine to -1.87+/-0.23kJmol(-1) for N-acetyl-L-methionine.
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PMID:Importance of product inhibition in the kinetics of the acylase hydrolysis reaction by differential stopped flow microcalorimetry. 1241 41

The induction of 2-amino-Delta(2)-thiazoline-4-carboxylic acid hydrolase (ATCase) and N-carbamoylcysteine amidohydrolase (NCCase), both of which are involved in the conversion step of 2-amino-Delta(2)-thiazoline carboxylic acid (ATC) to cysteine, was studied with Pseudomonas putida AJ3865. We found that L-ATC induced L-ATCase and L-NCCase, but that D-ATC induced only L-NCCase, whereas L- or D-NCC and thiazoline derivatives did not induce both enzymes. The bacterium showed neither D-ATCase nor D-NCCase activities, indicating that the role of L-ATC and D-ATC was different in the enzyme induction. We also found new inducers, d- and l-methionine, S-methyl-L-cysteine, cysteic acid, and 2-aminoethane sulfonic acid. However, the induction level of both enzymes by new inducers was much lower than those by L-ATC and D-ATC. Furthermore, the induction rate of both enzymes was synergistically increased only under a combination of D,L-ATC and new inducers. S-Compounds, however, such as new inducers except S-methyl-L-cysteine, inhibited both enzyme activities. This is the first report on the new inducers, synergistic induction, and the new inhibitors of L-ATCase and L-NCCase.
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PMID:Induction of 2-amino-D2-thiazoline-4-carboxylic acid hydrolase and N-carbamoyl-l-cysteine amidohydrolase by S-compounds in Pseudomonas putida AJ3865. 1248 19

Adenosine-to-inosine (A-to-I) RNA editing is a post-transcriptional process that amplifies the repertoire of protein production. Recently, the induction of this process through up-regulation of the editing enzyme RNA-specific adenosine deaminase 1 (ADAR1) was documented during acute inflammation. Here we report that the inflammation-induced up-regulation of ADAR1 involves differential production and intracellular localization of several isoforms with distinct RNA-binding domains and localization signals. These include the full-length ADAR1 (p150) and two functionally active short isoforms (p80 and p110). ADAR1 p80 starts at a methionine 519 (M519) due to alternative splicing in exon 2, which deletes the putative nuclear localization signal, the Z-DNA binding domain, and the entire RNA binding domain I. ADAR1 p110 is the mouse homologue of the human ADAR1 110-kDa variant (M246), which retains the second half of the Z-DNA binding domain, all RNA binding domains, and the deaminase domain. Additional variations are found in the third RNA binding domain of ADAR1; they are differentially regulated during inflammation, generating isoforms with different levels of activities. Studies in several cell types transfected with ADAR1-EGFP chimeras demonstrated that the p150 and p80 variants are localized in the cytoplasm and nucleolus, respectively. In agreement with this observation, endogenous ADAR1 was identified in the cytoplasm and nucleolus of mouse splenocytes and HeLa cells. Since the ADAR1 variants are differentially regulated during acute inflammation, it suggests that the localization of these variants and of A-to-I RNA editing in the cytoplasm, nucleus, and nucleolus is intracellularly reorganized in response to inflammatory stimulation.
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PMID:Intracellular localization of differentially regulated RNA-specific adenosine deaminase isoforms in inflammation. 1295 22


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