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

---

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

A combinatorial experimental technique was used to identify salts and salt mixtures capable of activating penicillin amidase in organic solvents for the transesterification of phenoxyacetate methyl ester with 1-propanol. Penicillin amidase was lyophilized in the presence of various chloride and acetate salts within 96-deep-well plates and catalytic rates measured to determine lead candidates for highly salt-activated preparations. The kinetics of the most active formulations were then further evaluated. These studies revealed that a formulation consisting of 98% (w/w) of a 1:1 KAc:CsCl salt mixture, 1% (w/w) enzyme, and 1% (w/w) potassium phosphate buffer was approximately 35,000-fold more active than the salt-free formulation in hexane, as reflected in values of V(max)/K(m). This extraordinary activation could be extended to more polar solvents, including tert-amyl alcohol, and to formulations with lower total salt contents. A correlation was found between the kosmotropic/chaotropic behavior of the salts (as measured by the Jones-Dole B coefficients) and the observed activation. Strongly chaotropic cations combined with strongly kosmotropic anions yielded the greatest activation, and this is likely due to the influence of the ions on protein-water and protein-salt interactions.
...
PMID:Combinatorial formulation of biocatalyst preparations for increased activity in organic solvents: salt activation of penicillin amidase. 1476 Jun 96

The object of the work is to evaluate whether rhizobacteria populating dry salty environments can increase resistance in tomato to salt stress. Seven strains of plant growth-promoting bacteria that have 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity were isolated from soil samples taken from the Arava region of southern Israel. Following growth of these seedlings in the presence of 43 mM NaCl for 7 weeks, the bacterium that promoted growth to the greatest extent was selected for further study. DNA analysis of the 16S RNA indicated that the selected bacterium was Achromobacter piechaudii. This bacterium significantly increased the fresh and dry weights of tomato seedlings grown in the presence of up to 172 mM NaCl salt. The bacterium reduced the production of ethylene by tomato seedlings, which was otherwise stimulated when seedlings were challenged with increasing salt concentrations, but did not reduce the content of sodium. However, it slightly increased the uptake of phosphorous and potassium, which may contribute in part to activation of processes involved in the alleviation of the effect of salt. In the presence of salt the bacterium increased the water use efficiency (WUE). This may suggest that the bacterium act to alleviate the salt suppression of photosynthesis. However, the detailed mechanism was not elucidated. The work described in this report is a first step in the development of productive agricultural systems in saline environments.
...
PMID:Plant growth-promoting bacteria confer resistance in tomato plants to salt stress. 1524 71

Early on, we reported the partial purification of prophenoloxidase-activating proteinase-1 (PAP-1) from the tobacco hornworm, Manduca sexta [Proc. Natl. Acad. Sci. USA 95 (1998) 12220]. PAP-1 requires an auxiliary factor for generating active phenoloxidase (PO) [Insect Biochem. Mol. Biol. 33 (2003) 197; Insect Biochem. Mol. Biol. 34 (2004) 731]. To further characterize their roles in the proteolytic activation of prophenoloxidase (proPO), we purified PAP-1 to near homogeneity by hydroxylapatite, dextran sulfate, gel filtration, and lectin affinity chromatography. With 2.4 x 10(3)-fold purification and 20% yield, we obtained 63 microg PAP-1 from about 120 M. sexta prepupal cuticles (approximately 400 g). The purified glycoprotein (Mr=39,810+/-20; pI=5.6) had the highest amidase activity at pH 8.0 and a low salt concentration. The optimal conditions for proPO activation by PAP-1 and SPHs were: pH 8.0-8.4, PAP:SPH=1.5:1, and 0-10 degrees C for 40-50 min. While PAP-1 and SPHs are reasonably heat stable, PO activity generated after 1h incubation was lower at 20 or 30 degrees C than 0-10 degrees C because activated PO was unstable at a higher temperature. The KMs of PAP-1 toward IEARpNA and proPO were 201+/-18 microM and 16.6+/-3.0 microg/ml, respectively, and the absence of SPHs did not significantly affect KM for the synthetic substrate. PO activity and proPO cleavage were reduced in reaction mixtures containing the same amounts of proPO, PAP-1, and SPHs but increasing concentrations of NaCl. Ionic strength of the reaction buffer may reduce proPO-PAP-SPH interactions, proPO processing, and PO assembly.
...
PMID:Purification and characterization of Manduca sexta prophenoloxidase-activating proteinase-1, an enzyme involved in insect immune responses. 1564 78

Listeria monocytogenes must resist the deleterious actions of bile in order to infect and subsequently colonize the human gastrointestinal tract. The molecular mechanisms used by the bacterium to resist bile and the influence of bile on pathogenesis are as yet largely unexplored. This study describes the analysis of three genes--bsh, pva, and btlB--previously annotated as bile-associated loci in the sequenced L. monocytogenes EGDe genome (lmo2067, lmo0446, and lmo0754, respectively). Analysis of deletion mutants revealed a role for all three genes in resisting the acute toxicity of bile and bile salts, particularly glycoconjugated bile salts at low pH. Mutants were unaffected in the other stress responses examined (acid, salt, and detergents). Bile hydrolysis assays demonstrate that L. monocytogenes possesses only one bile salt hydrolase gene, namely, bsh. Transcriptional analyses and activity assays revealed that, although it is regulated by both PrfA and sigma(B), the latter appears to play the greater role in modulating bsh expression. In addition to being incapable of bile hydrolysis, a sigB mutant was shown to be exquisitely sensitive to bile salts. Furthermore, increased expression of sigB was detected under anaerobic conditions and during murine infection. A gene previously annotated as a possible penicillin V amidase (pva) or bile salt hydrolase was shown to be required for resistance to penicillin V but not penicillin G but did not demonstrate a role in bile hydrolysis. Finally, animal (murine) studies revealed an important role for both bsh and btlB in the intestinal persistence of L. monocytogenes.
...
PMID:Contribution of three bile-associated loci, bsh, pva, and btlB, to gastrointestinal persistence and bile tolerance of Listeria monocytogenes. 1566 31

Bacterial bile salt hydrolases catalyze the degradation of conjugated bile acids in the mammalian gut. The crystal structures of conjugated bile acid hydrolase (CBAH) from Clostridium perfringens as apoenzyme and in complex with taurodeoxycholate that was hydrolyzed to the reaction products taurine and deoxycholate are described here at 2.1 and 1.7 A resolution, respectively. The crystal structures reveal close relationship between CBAH and penicillin V acylase from Bacillus sphaericus. This similarity together with the N-terminal cysteine classifies CBAH as a member of the N-terminal nucleophile (Ntn) hydrolase superfamily. Both crystal structures show an identical homotetrameric organization with dihedral (D(2) or 222) point group symmetry. The structure analysis of C. perfringens CBAH identifies critical residues in catalysis, substrate recognition, and tetramer formation which may serve in further biochemical characterization of bile acid hydrolases.
...
PMID:Conjugated bile acid hydrolase is a tetrameric N-terminal thiol hydrolase with specific recognition of its cholyl but not of its tauryl product. 1582 32

Monoclonal antibodies (MAbs) against mutant (T103I) amidase from Pseudomonas aeruginosa were raised by hybridoma technology. To select MAbs suitable for immunoaffinity chromatography, hybridoma clones secreting polyol-responsive MAbs (PR-MAbs) were screened that bind antigen tightly but release under mild and nondenaturing elution conditions. It was found that about 10% of enzyme-linked immunosorbent assay (ELISA)-positive hybridoma produce these MAbs as their ag-ab complex can be disrupted by propylene glycol in the presence of a suitable salt. Two of these hybridoma clones (F6G7 and E2A6) secreting PR-MAbs against mutant amidase were selected for optimization of experimental conditions for elution of amidase by using ELISA elution assay. These hybridoma cell lines secreted MAbs of IgM class that were purified in a single step by gel filtration chromatography, which revealed a single protein band on native polyacrylamide gel electrophoresis (PAGE). Specificity studies of this MAb revealed that it recognized specifically a common epitope on mutant and wild-type amidases as determined by direct ELISA. This MAb exhibited a higher affinity for denatured forms of wild-type and mutant amidases than for native forms as revealed by affinity constants (K), suggesting that it recognizes a cryptic epitope on an amidase molecule. Furthermore, MAb E2A6 inhibited about 60% of wild-type amidase activity, whereas it activated about 60% of mutant amidase (T103I) activity. The data presented in this work suggest that this MAb acts as a very useful probe to detect conformational changes in native and denatured amidases as well as to differentiate wild-type and mutant (T103I) amidases.
...
PMID:Characterization of monoclonal antibodies against altered (T103I) amidase from Pseudomonas aeruginosa. 1598 46

During adaptation of barley (Hordeum vulgare L.) seedlings to extremely high concentrations of sodium chloride in the root space, the content of galactolipids of chloroplast membranes decreased considerably. Alterations in membrane lipids were due to the high concentration of ions rather than to the increase in the water potential. Sodium chloride was accumulated in the leaf cells and affected lipid-synthesizing enzymes such as galactosyl transferase and acylase which are attached to the chloroplast envelope. The return of salt-adapted barley seedlings to a nutrient solution with low salt concentration resulted in a reversal of the observed changes. It is suggested that the decrease in content of galactolipids in biomembranes is one of the factors causing increased salt resistance in barley plants which are adapted to extreme salinity.
...
PMID:Changes in Chloroplast Membrane Lipids during Adaptation of Barley to Extreme Salinity. 1666 May 10

To investigate the physiological basis of salt adaptation in poplar, we compared the effect of salt stress on wood anatomy and auxin physiology of the salt-resistant Populus euphratica and salt-sensitive Populus x canescens. Both poplar species showed decreases in vessel lumina associated with increases in wall strength in response to salt, however, in P. euphratica at three-fold higher salt concentrations than in P. x canescens. The predicted hydraulic conductivity of the wood formed under salt stress decreased in P. x canescens, while in P. euphratica, no significant effects of salt on conductivity and transpiration were observed. The concentration of free indole-3-acetic acid (IAA) decreased under salt stress in the xylem of both poplar species, but to a larger extent in P. x canescens than in P. euphratica. Only salt-treated P. euphratica exhibited an increase in IAA-conjugates in the xylem. Genes homologous to the auxin-amidohydrolase ILL3 were isolated from the xylems of P. euphratica and P. x canescens. For functional analysis, the auxin-amidohydrolase from P. x canescens was overexpressed in Arabidopsis. Transgenic Arabidopsis plants were more resistant to salt stress than the wild-type plants. Increased sensitivity of the transgenic Arabidopsis to IAA-Leu showed that the encoded hydrolase used IAA-Leu as a substrate. These results suggest that poplar can use IAA-amidoconjugates in the stem as a source of auxin to balance the effects of salt stress on auxin physiology.
...
PMID:Adaptation to high salinity in poplar involves changes in xylem anatomy and auxin physiology. 1689 15

Bile salt hydrolase (BSH) is an enzyme produced by the intestinal microflora that catalyzes the deconjugation of glycine- or taurine-linked bile salts. The crystal structure of BSH reported here from Bifidobacterium longum reveals that it is a member of N-terminal nucleophil hydrolase structural superfamily possessing the characteristic alphabetabetaalpha tetra-lamellar tertiary structure arrangement. Site-directed mutagenesis of the catalytic nucleophil residue, however, shows that it has no role in zymogen processing into its corresponding active form. Substrate specificity was studied using Michaelis-Menten and inhibition kinetics and fluorescence spectroscopy. These data were compared with the specificity profile of BSH from Clostridium perfrigens and pencillin V acylase from Bacillus sphaericus, for both of which the three-dimensional structures are available. Comparative analysis shows a gradation in activity toward common substrates, throwing light on a possible common route toward the evolution of pencillin V acylase and BSH.
...
PMID:Structural and functional analysis of a conjugated bile salt hydrolase from Bifidobacterium longum reveals an evolutionary relationship with penicillin V acylase. 1690 39

Nitriles are important environmental compounds, both as natural products and industrial pollutants. Until now, there have been no data on the possibility of microbial nitrile degradation at high pH/salt conditions. Acetonitrile (CH(3)C(triple bond)N) is the simplest organic nitrile. Here, evidence is provided of microbial utilization of acetonitrile as a carbon, energy and nitrogen source at extremely high pH and moderate salinity. Positive enrichment cultures with acetonitrile at pH 10 and salt content equivalent to 0.6 M total Na(+) were obtained from mixed sediment samples from soda lakes, but not from soda soils. Purification of these cultures resulted in the isolation of two bacterial strains capable of growth with acetonitrile as sole carbon, energy and nitrogen source under haloalkaline conditions. Apart from acetonitrile, the bacteria also grew with propionitrile. Nitrile hydrolysis to acetamide was identified as the rate-limiting step of acetonitrile degradation via the nitrile hydratase/amidase pathway. The new bacteria belonged to moderately salt-tolerant obligate alkaliphiles with optimum growth at pH 10 and 0.5 M total Na(+). The cells were yellow-coloured due to a high concentration of carotenoids dominated by zeaxanthin. Phylogenetic analysis placed the isolates into a new lineage within the family Ectothiorhodospiraceae in the Gammaproteobacteria. On the basis of unique phenotypic properties and their separate phylogenetic position, the new bacteria are placed into a new genus and species for which the name Natronocella acetinitrilica gen. nov., sp. nov is proposed.
...
PMID:Acetonitrile degradation under haloalkaline conditions by Natronocella acetinitrilica gen. nov., sp. nov. 1737 25


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---