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)

Cytosolic extracts of boar sperm contain a soluble phospholipase C (PLC) activity that induces Ca2+ release in sea-urchin (Lytechinus pictus) egg homogenates and an uncharacterized protein factor that causes Ca2+ oscillations when injected into mammalian eggs. In the present study we fractionated boar sperm extracts on three different FPLC chromatographic columns and found that the fractions that caused maximal Ca2+ release in sea-urchin egg homogenates were also the ones that triggered Ca2+ oscillations in mouse eggs. Our data suggests that the sperm factor which triggers Ca2+ oscillations in eggs contains a PLC and not the 33 kDa glucosamine deaminase previously suggested to be one its components.
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PMID:The soluble sperm factor that causes Ca2+ release from sea-urchin (Lytechinus pictus) egg homogenates also triggers Ca2+ oscillations after injection into mouse eggs. 1037 37

Mammalian glucosamine 6-phosphate deaminase (GNPDA) was first detected in hamster spermatozoa. To further elucidate its role, we have cloned mouse GNPDA and produced a polyclonal rabbit anti-GNPDA antibody. This antibody recognized a 33 kDa protein in soluble extracts from mouse brain, liver, kidney, muscle, ovary, testis and sperm. Immunofluorescent analysis of the localization of GNPDA in male reproductive tissue revealed its presence in spermatids and in spermatozoa. In spermatids, GNPDA localized close to the developing acrosome vesicle and in spermatozoa close to the acrosomal region. Following the induction of the acrosome reaction, GNPDA fluorescence in spermatozoa was either reduced or GNPDA was absent. These data suggest that GNPDA might play a role in the acrosome reaction.
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PMID:Characterization of testicular mouse glucosamine 6-phosphate deaminase (GNPDA). 1048 Oct 53

Among enteric bacteria, the ability to grow on N-acetyl-galactosamine (GalNAc or Aga) and on D-galactosamine (GalN or Gam) differs. Thus, strains B, C and EC3132 of Escherichia coli are Aga+ Gam+ whereas E. coli K-12 is Aga- Gam-, similarly to Klebsiella pneumoniae KAY2026, Klebsiella oxytoca M5a1 and Salmonella typhimurium LT2. The former strains carry a complete aga/kba gene cluster at 70.5 min of their gene map. These genes encode an Aga-specific phosphotransferase system (PTS) or IIAga (agaVWE) and a GalN-specific PTS or IIGam (agaBCD). Both PTSs belong to the mannose-sorbose family, i.e. the IIB, IIC and IID domains are encoded by different genes, and they share a IIA domain (agaF). Furthermore, the genes encode an Aga6P-deacetylase (agaA), a GalN6P deaminase (agaI), a tagatose-bisphosphate aldolase comprising two different peptides (kbaYZ) and a putative isomerase (agaS), i.e. complete pathways for the transport and degradation of both amino sugars. The genes are organized in two adjacent operons (kbaZagaVWEFA and agaS kbaYagaBCDI) and controlled by a repressor AgaR. Its gene agaR is located upstream of kbaZ, and AgaR responds to GalNAc and GalN in the medium. All Aga- Gam- strains, however, carry a deletion covering genes agaW' EF 'A; consequently they lack active IIAga and IIGam PTSs, thus explaining their inability to grow on the two amino sugars. Remnants of a putative recombination site flank the deleted DNA in the various Aga- Gam- enteric bacteria. Derivatives with an Aga+ Gam- phenotype can be isolated from E. coli K-12. These retain the DeltaagaW' EF 'A deletion and carry suppressor mutations in the gat and nag genes for galactitol and N-acetyl-glucosamine metabolism, respectively, that allow growth on Aga but not on GalN.
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PMID:Pathways for the utilization of N-acetyl-galactosamine and galactosamine in Escherichia coli. 1093 10

The active site of glucosamine-6-phosphate deaminase (EC 3.5.99.6, formerly 5.3.1.10) from Escherichia coli was first characterized on the basis of the crystallographic structure of the enzyme bound to the competitive inhibitor 2-amino-2-deoxy-glucitol 6-phosphate. The structure corresponds to the R allosteric state of the enzyme; it shows the side-chain of His143 in close proximity to the O5 atom of the inhibitor. This arrangement suggests that His143 could have a role in the catalysis of the ring-opening step of glucosamine 6-phosphate whose alpha-anomer is the true substrate. The imidazole group of this active-site histidine contacts the carboxy groups from Glu148 and Asp141, via its Ndelta1 atom [Oliva et al. (1995) Structure 3, 1323-1332]. These interactions change in the T state because the side chain of Glu148 moves toward the allosteric site, leaving at the active site the dyad Asp141-His143 [Horjales et al. (1999) Structure 7, 527-536]. In this research, a dual approach using site-directed mutagenesis and controlled chemical modification of histidine residues has been used to investigate the role of the active-site histidine. Our results support a multifunctional role of His143; in the forward reaction, it is involved in the catalysis of the ring-opening step of the substrate, glucosamine 6-P. In the reverse reaction, the substrate fructose 6-P binds in its open chain, carbonylic form. The role of His143 in the binding of both glucosamine 6-P and reaction intermediates in their extended-chain forms was demonstrated by binding experiments using the reaction intermediate analogue, 2-amino-2-deoxy-D-glucitol 6-phosphate. His143 was also shown to be a critical residue for the conformational coupling between active and allosteric sites. From the pH dependence of the reactivity of the active site histidine to diethyl dicarbonate, we observed a pK(a) change of 1.2 units to the acid side when the enzyme undergoes the allosteric T to R transition during which the side chain of Glu148 moves toward the active site. The kinetic study of the Glu148-Gln mutant deaminase shows that the loss of the carboxy group and its replacement with the corresponding amide modifies the k(cat) versus pH profile of the enzyme, suggesting that the catalytic step requiring the participation of His143 has become rate-limiting. This, in turn, indicates that the interaction Glu148-His143 in the wild-type enzyme in the R state contributes to make the enzyme functional over a wide pH range.
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PMID:On the multiple functional roles of the active site histidine in catalysis and allosteric regulation of Escherichia coli glucosamine 6-phosphate deaminase. 1151 96

The cyst wall of Giardia intestinalis contains proteins and a novel N-acetylgalactosamine (GalNAc) polysaccharide, which is its major constituent. GalNAc is not present in growing trophozoites, but is synthesized during encystment via an inducible pathway of enzymes that produce UDP-GalNAc from fructose 6-phosphate. This report focuses on the regulation of these enzymes and thus the genes for glucosamine 6-phosphate N-acetyltransferase (GNA), phosphoacetylglucosamine mutase (AGM), UDP-N-acetylglucosamine pyrophosphorylase (UAP), and UDP-N-acetylglucosamine 4-epimerase (UAE) were cloned and expressed in Escherichia coli. Each of these expressed enzymes had the predicted activity and was used to generate antibodies. Northern and Western blot analyses demonstrated that both the mRNA and protein levels for all of these enzymes increase during encystment. Nuclear run-on assays of these and the previously analyzed glucosamine 6-phosphate deaminase (GNP; glucosamine 6-P isomerase) showed that all of the genes responsible for UDP-GalNAc synthesis during encystment are induced at the transcription level.
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PMID:Transcription regulation is demonstrated for five key enzymes in Giardia intestinalis cyst wall polysaccharide biosynthesis. 1270 96

1. Glucosamine 6-phosphate deaminase [2-amino-2-deoxy-d-glucose 6-phosphate ketol-isomerase (deaminating), EC 5.3.1.10] of Bacillus subtilis has been partially purified. Its K(m) is 3.0mm. 2. Extracts of B. subtilis contain N-acetylglucosamine 6-phosphate deacetylase (K(m) 1.4mm), glucosamine 1-phosphate acetylase and amino sugar kinases (EC 2.7.1.8 and 2.7.1.9). 3. Glucosamine 6-phosphate synthetase (l-glutamine-d-fructose 6-phosphate aminotransferase, EC 2.6.1.16) is repressed by growth of B. subtilis in the presence of glucosamine, N-acetylglucosamine, N-propionylglucosamine or N-formylglucosamine. Glucosamine 6-phosphate deaminase and N-acetylglucosamine 6-phosphate deacetylase are induced by N-acetylglucosamine. Amino sugar kinases are induced by glucose, glucosamine and N-acetylglucosamine. The synthesis of glucosamine 1-phosphate acetylase is unaffected by amino sugars. 4. Glucose in the growth medium prevents the induction of glucosamine 6-phosphate deaminase and of N-acetylglucosamine 6-phosphate deacetylase caused by N-acetylglucosamine; glucose also alleviates the repression of glucosamine 6-phosphate synthetase caused by amino sugars. 5. Glucosamine 6-phosphate deaminase increases in bacteria incubated beyond the exponential phase of growth. This increase is prevented by glucose.
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PMID:FURTHER STUDIES ON THE REGULATION OF AMINO SUGAR METABOLISM IN BACILLUS SUBTILIS. 1434 23

Glucosamine 6-phosphate is converted to fructose 6-phosphate and ammonia by the action of the enzyme glucosamine 6-phosphate deaminase, NagB. This reaction is the final step in the specific GlcNAc utilization pathway and thus decides the metabolic fate of GlcNAc. Sequence analyses suggest that the NagB "superfamily" consists of three main clusters: multimeric and allosterically regulated glucosamine-6-phosphate deaminases (exemplified by Escherichia coli NagB), phosphogluconolactonases, and monomeric hexosamine-6-phosphate deaminases. Here we present the three-dimensional structure and kinetics of the first member of this latter group, the glucosamine-6-phosphate deaminase, NagB, from Bacillus subtilis. The structures were determined in ligand-complexed forms at resolutions around 1.4 Angstroms. BsuNagB is monomeric in solution and as a consequence is active (k(cat) 28 s(-1), K(m(app)) 0.13 mM) without the need for allosteric activators. A decrease in activity at high substrate concentrations may reflect substrate inhibition (with K(i) of approximately 4 mM). The structure completes the NagB superfamily structural landscape and thus allows further interrogation of genomic data in terms of the regulation of NagB and the metabolic fate(s) of glucosamine 6-phosphate.
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PMID:Structure and kinetics of a monomeric glucosamine 6-phosphate deaminase: missing link of the NagB superfamily? 1575 26

Wild-type Escherichia coli grows more slowly on glucosamine (GlcN) than on N-acetylglucosamine (GlcNAc) as a sole source of carbon. Both sugars are transported by the phosphotransferase system, and their 6-phospho derivatives are produced. The subsequent catabolism of the sugars requires the allosteric enzyme glucosamine-6-phosphate (GlcN6P) deaminase, which is encoded by nagB, and degradation of GlcNAc also requires the nagA-encoded enzyme, N-acetylglucosamine-6-phosphate (GlcNAc6P) deacetylase. We investigated various factors which could affect growth on GlcN and GlcNAc, including the rate of GlcN uptake, the level of induction of the nag operon, and differential allosteric activation of GlcN6P deaminase. We found that for strains carrying a wild-type deaminase (nagB) gene, increasing the level of the NagB protein or the rate of GlcN uptake increased the growth rate, which showed that both enzyme induction and sugar transport were limiting. A set of point mutations in nagB that are known to affect the allosteric behavior of GlcN6P deaminase in vitro were transferred to the nagB gene on the Escherichia coli chromosome, and their effects on the growth rates were measured. Mutants in which the substrate-induced positive cooperativity of NagB was reduced or abolished grew even more slowly on GlcN than on GlcNAc or did not grow at all on GlcN. Increasing the amount of the deaminase by using a nagC or nagA mutation to derepress the nag operon improved growth. For some mutants, a nagA mutation, which caused the accumulation of the allosteric activator GlcNAc6P and permitted allosteric activation, had a stronger effect than nagC. The effects of the mutations on growth in vivo are discussed in light of their in vitro kinetics.
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PMID:Why does Escherichia coli grow more slowly on glucosamine than on N-acetylglucosamine? Effects of enzyme levels and allosteric activation of GlcN6P deaminase (NagB) on growth rates. 1583 23

Engineered glucosamine 6-phosphate deaminase of Escherichia coli with unique reactive cysteines at positions 164 or 206 was created by site-directed mutagenesis to monitor the allosteric transition in solution by the fluorescence emission of the bimane or dansyl-amidoethyl groups attached to the indicated residues. The selection of both positions was due to the differential interaction of these residues between T- and R-conformers at the interface of two trimers that form the hexameric structure; in the T-conformer, residue 164 or 206 presents only intrasubunit contacts, but in the R-conformer, new intersubunit contacts are established. As in the wild-type enzyme, fluorescent-labeled mutants show no modification on the allosteric activation of the K-system, only the kcat was reduced to a value of 72 s(-1) (approximately 50% of wild-type). With these preparations, conformational changes were detected by the fluorescence emission spectra at steady state when the active site or the allosteric site ligands were titrated. Despite the similar changes in the fluorescence spectra that were correlated with the induction of the R-state, differences were observed at the maximal change in the fluorescence spectra and in the relative solvent polarities at the positions labeled. These data suggested structural differences in the conformation of the R-state when it is induced from the active site or from the allosteric site, which is not consistent with the two-state structural model proposed by previous crystallographic studies of this enzyme.
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PMID:Site-directed fluorescence labeling reveals differences on the R-conformer of glucosamine 6-phosphate deaminase of Escherichia coli induced by active or allosteric site ligands at steady state. 1628 12

The SMU.636 protein from Streptococcus mutans is a putative glucosamine 6-phosphate deaminase with 233 residues. The smu.636 gene was PCR-amplified from S. mutans genomic DNA and cloned into the expression vector pET-28a(+). The resultant His-tagged fusion protein was expressed in Escherichia coli and purified to homogeneity in two steps. Crystals of the fusion protein were obtained by the hanging-drop vapour-diffusion method. The crystals diffracted to 2.4 A resolution and belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 53.83, b = 82.13, c = 134.70 A.
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PMID:Protein preparation and preliminary X-ray crystallographic analysis of a putative glucosamine 6-phosphate deaminase from Streptococcus mutants. 1776 62


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