Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.2.1.1 (ACS)
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CheY, a response regulator of the chemotaxis system in Escherichia coli, can be activated by either phosphorylation or acetylation to generate clockwise rotation of the flagellar motor. Both covalent modifications are involved in chemotaxis, but the function of the latter remains obscure. To understand why two different modifications apparently activate the same function of CheY, we studied the effect that each modification exerts on the other. The phosphodonors of CheY, the histidine kinase CheA and acetyl phosphate, each strongly inhibited both the autoacetylation of the acetylating enzyme, acetyl-CoA synthetase (Acs), and the acetylation of CheY. CheZ, the enzyme that enhances CheY dephosphorylation, had the opposite effect and enhanced Acs autoacetylation and CheY acetylation. These effects of the phosphodonors and CheZ were not caused by their respective activities. Rather, they were caused by their interactions with Acs and, possibly, with CheY. In addition, the presence of Acs elevated the phosphorylation levels of both CheA and CheY, and acetate repressed this stimulation. These observations suggest that CheY phosphorylation and acetylation are linked and co-regulated. We propose that the physiological role of these mutual effects is at two levels: linking chemotaxis to the metabolic state of the cell, and serving as a tuning mechanism that compensates for cell-to-cell variations in the concentrations of CheA and CheZ.
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PMID:Co-regulation of acetylation and phosphorylation of CheY, a response regulator in chemotaxis of Escherichia coli. 1532 41

In-vitro deposition of calcium phosphate layer (CPL) on metallic substrate requires special surface preparation in order to provide an interfacial bond. In this work 316 stainless steel surface is modified through deposition of a thin film ( approximately 0.5 microm) of sol-gel hydroxyapatite (SG-HA). This well-bonded film acts as an intermediary and nucleation surface of the CPL film. The SG-HA films were annealed at 375 degrees C (samples coded 375-ACS) and 400 degrees C (400-ACS) to achieve different crystallinity of the films, and thus to affect and study the CPL nucleation process. The CPL growth was investigated in terms of deposition kinetics and microstructural development. A deposition rate of dense CPL of about 0.43 microm/day was achieved on the crystallized film of 400-ACS, and 0.22 microm/day of porous CPL on amorphous 375-ACS. A compositional variation of Ca/P ratio across the CPL film thickness (400-ACS) was observed. Lower Ca/P ratio of 1.2 was detected near the substrate-CPL interface and about 1.5 near the solution-CPL interface. Infrared analysis showed the CPL to be of apatitic calcium-deficient structure. Kinetic model explaining the advancement of the CPL upon the in-vitro immersion is proposed.
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PMID:In-vitro forming of calcium phosphate layer on sol-gel hydroxyapatite-coated metal substrates. 1534 91

Gateways to Clinical Trials is a guide to the most recent clinical trials in current literature and congresses. The data in the following tables have been retrieved from the Clinical Trials Knowledge Area of Prous Science Integrity, the drug discovery and development portal, http://integrity.prous.com. This issue focuses on the following selection of drugs: Abiraterone acetate, acyline, adalimumab, adenosine triphosphate, AEE-788, AIDSVAX gp120 B/B, AK-602, alefacept, alemtuzumab, alendronic acid sodium salt, alicaforsen sodium, alprazolam, amdoxovir, AMG-162, aminolevulinic acid hydrochloride, aminolevulinic acid methyl ester, aminophylline hydrate, anakinra, anecortave acetate, anti-CTLA-4 MAb, APC-8015, aripiprazole, aspirin, atazanavir sulfate, atomoxetine hydrochloride, atorvastatin calcium, atrasentan, AVE-5883, AZD-2171; Betamethasone dipropionate, bevacizumab, bimatoprost, biphasic human insulin (prb), bortezomib, BR-A-657, BRL-55730, budesonide, busulfan; Calcipotriol, calcipotriol/betamethasone dipropionate, calcium folinate, capecitabine, capravirine, carmustine, caspofungin acetate, cefdinir, certolizumab pegol, CG-53135, chlorambucil, ciclesonide, ciclosporin, cisplatin, clofarabine, clopidogrel hydrogensulfate, clozapine, co-trimoxazole, CP-122721, creatine, CY-2301, cyclophosphamide, cypher, cytarabine, cytolin; D0401, darbepoetin alfa, darifenacin hydrobromide, DASB, desipramine hydrochloride, desloratadine, desvenlafaxine succinate, dexamethasone, didanosine, diquafosol tetrasodium, docetaxel, doxorubicin hydrochloride, drotrecogin alfa (activated), duloxetine hydrochloride, dutasteride; Ecallantide, efalizumab, efavirenz, eletriptan, emtricitabine, enfuvirtide, enoxaparin sodium, estramustine phosphate sodium, etanercept, ethinylestradiol, etonogestrel, etonogestrel/ethinylestradiol, etoposide, exenatide; Famciclovir, fampridine, febuxostat, filgrastim, fludarabine phosphate, fluocinolone acetonide, fluorouracil, fluticasone propionate, fluvastatin sodium, fondaparinux sodium; Gaboxadol, gamma-hydroxybutyrate sodium, gefitinib, gelclair, gemcitabine, gemfibrozil, glibenclamide, glyminox; Haloperidol, heparin sodium, HPV 16/HPV 18 vaccine, human insulin, human insulin; Icatibant, imatinib mesylate, indium 111 (111In) ibritumomab tiuxetan, infliximab, INKP-100, iodine (I131) tositumomab, IoGen, ipratropium bromide, ixabepilone; L-870810, lamivudine, lapatinib, laquinimod, latanoprost, levonorgestrel, licochalcone a, liposomal doxorubicin, lopinavir, lopinavir/ritonavir, lorazepam, lovastatin; Maraviroc, maribavir, matuzumab, MDL-100907, melphalan, methotrexate, methylprednisolone, mitomycin, mitoxantrone hydrochloride, MK-0431, MN-001, MRKAd5 HIV-1 gag/pol/nef, MRKAd5gag, MVA.HIVA, MVA-BN Nef, MVA-Muc1-IL-2, mycophenolate mofetil; Nelfinavir mesilate, nesiritide, NSC-330507; Olanzapine, olmesartan medoxomil, omalizumab, oral insulin, osanetant; PA-457, paclitaxel, paroxetine, paroxetine hydrochloride, PCK-3145, PEG-filgrastim, peginterferon alfa-2a, peginterferon alfa-2b, perillyl alcohol, pexelizumab, pimecrolimus, pitavastatin calcium, porfiromycin, prasterone, prasugrel, pravastatin sodium, prednisone, pregabalin, prinomastat, PRO-2000, propofol, prostate cancer vaccine; Rasagiline mesilate, rhBMP-2/ACS, rhBMP-2/BCP, rhC1, ribavirin, rilpivirine, ritonavir, rituximab, Ro-26-9228, rosuvastatin calcium, rosuvastatin sodium, rubitecan; Selodenoson, simvastatin, sirolimus, sitaxsentan sodium, sorafenib, SS(dsFv)-PE38, St. John's Wort extract, stavudine; Tacrolimus, tadalafil, tafenoquine succinate, talaglumetad, tanomastat, taxus, tegaserod maleate, telithromycin, tempol, tenofovir, tenofovir disoproxil fumarate, testosterone enanthate, TH-9507, thalidomide, tigecycline, timolol maleate, tiotropium bromide, tipifarnib, torcetrapib, trabectedin, travoprost, travoprost/timolol, treprostinil sodium; Valdecoxib, vardenafil hydrochloride hydrate, varenicline, VEGF-2 gene therapy, venlafaxine hydrochloride, vildagliptin, vincristine sulfate, voriconazole, VRX-496, VX-385; Warfarin sodium; Ximelagatran; Yttrium 90 (90Y) ibritumomab tiuxetan; Zanolimumab, zidovudine.
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PMID:Gateways to clinical trials. 1608 22

In this study, we used proteomics to better understand the growth on glucose of Escherichia coli in high cell density, fed-batch cultures and the response to overexpression of plasmid-encoded 6-phosphogluconolactonase (PGL). Using liquid chromatography coupled to electrospray mass spectrometry, at least 300 proteins were identified in the cytosolic fraction of the six time points used to monitor the fermentation. The relative abundance changes of selected proteins were obtained by comparing the peak area of the corresponding peptides at a particular m/z (mass over charge ratio) value. During the time course of samples collected during the rapid growth achieved under batch and fed-batch conditions, both the control and recombinant E. coli strains showed up-regulation of proteins participating in the tricarboxylic acid (TCA) cycle, particularly acetyl-CoA synthetase (AcCoAS), malate dehydrogenase (MDH), and succinyl-CoA synthetase (SuccCoAS). In the recombinant strain culture, fumarase was up-regulated until 35 h after inoculation but was not in the control strain culture. In addition, the proteomic measurement detected up-regulation of three well-characterized binding transport proteins in both control and recombinant strains. The up-regulation of TCA cycle enzymes is consistent with the increase in growth rate observed in the cell culture. In addition, up-regulation of these proteins demonstrated the importance of both the pentose-phosphate shunt and TCA cycle to the increased biosynthetic activity required by a high level protein synthesis. This study shows the potential of proteomics using shotgun sequencing (LC/MS of tryptic digests) to measure global changes in protein abundance during a fermentation process and will facilitate the development of robust manufacturing systems.
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PMID:Proteomic profiling of Escherichia coli proteins under high cell density fed-batch cultivation with overexpression of phosphogluconolactonase. 1620 43

Hyperthermophiles, a group of microorganisms whose optimum growth temperatures are above 80 degrees C, have been isolated mainly from marine and continental volcanic environments. They are viewed as potential sources of extraordinarily stable biomolecules with applications in novel industrial processes. Most hyperthermophiles belong to the domain Archaea, the third domain of life, and are considered to be the most ancient of all extant life forms. Recent studies have revealed unusual energy metabolic processes in hyperthermophilic archaea, e.g. a modified Embden-Meyerhof pathway, that have not been observed so far in organisms belonging to the Bacteria and Eucarya domains. Several novel enzymes--ADP-dependent glucokinase, ADP-dependent phosphofruktokinase, glyceraldehyde-3-phosphate ferredoxin oxidoreductase, phosphoenolpyruvate synthase, pyruvate: ferredoxin oxidoreductase, and ADP-forming acetyl-CoA synthetase--have been found to be involved in the modified Embden-Meyerhof pathway of the hyperthermophilic archaeon Pyrococcus furiosus. In addition, a novel regulation site for energy metabolism and a unique mode of ATP regeneration have been postulated to exist in the pathway of P. furiosus. The metabolic design observed in this microorganism might reflect the situation at an early stage of evolution. This review focuses mainly on the unique energy metabolism and related enzymes of P. furiosus that have recently been described.
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PMID:Novel energy metabolism in anaerobic hyperthermophilic archaea: a modified Embden-Meyerhof pathway. 1623 30

The lipoamide dehydrogenase (LPD) encoded by lpdA gene is a component of the pyruvate dehydrogenase complex (PDHc), alpha-ketoglutarate dehydrogenase (AKGDH) and the glycine cleavage multi-enzyme (GCV) systems. In the present study, cell growth characteristics, enzyme activities and intracellular metabolite concentrations were compared between the parent strain Escherichia coli BW25113 and its lpdA knockout mutant in batch and continuous cultures. The lpdA knockout mutant produced significantly more pyruvate and L-glutamate under aerobiosis. Some D-lactate and succinate also accumulated in the culture broth. Based on the investigation of enzyme activities and intracellular metabolite concentrations, acetyl-CoA was considered to be formed by the combined reactions through pyruvate oxidase (PoxB), acetyl-CoA synthetase (Acs) and acetate kinase (Ack)-phosphoacetyltransferase (Pta) in the lpdA mutant. The effect of the lpdA gene knockout on the intracellular metabolic flux distributions was investigated based on 1H-13C NMR spectra and GC-MS signals obtained from 13C-labeling experiment using the mixture of [U-13C] glucose, [1-13C] glucose, and naturally labeled glucose. Flux analysis of the lpdA mutant indicated that the Entner-Doudoroff (ED) pathway and the glyoxylate shunt were activated. The fluxes through glycolysis and oxidative pentose phosphate (PP) pathway (except for the flux through glucose-6-phosphate dehydrogenase) were slightly downregulated. The TCA cycle was also downregulated in the mutant strain. On the other hand, the fluxes through the anaplerotic reactions of PEP carboxylase, PEP carboxykinase and malic enzyme were upregulated, which were consistent with the results of enzyme activities. Furthermore, the influence of the poxB gene knockout on the growth of E. coli was also studied because of its similar function to PDHc which connects the glycolysis to the TCA cycle. Under aerobiosis, a comparison of lpdA mutant and poxB mutant indicated that PDHc is the main enzyme which catalyzes the reaction from pyruvate to acetyl-CoA in the parent strain, while PoxB plays a very important role in the PDHc-deficient strain.
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PMID:Effect of lpdA gene knockout on the metabolism in Escherichia coli based on enzyme activities, intracellular metabolite concentrations and metabolic flux analysis by 13C-labeling experiments. 1631 Feb 73

The proteins of HL type cytoplasmic male sterility rice anther of YTA (CMS) and YTB (maintenance line) were separated by two-dimensional electrophoresis with immobilized ph (3-10 non-linear) gradients as the first dimension and SDS-PAGE as the second. The silver-stained proteins spots were analyzed using Image Master 2D software, there were about 1800 detectable spots on each 2D-gel, and about 85 spots were differential expressed. With direct MALDI-TOF mass spectrometry analysis and protein database searching, 9 protein spots out of 16 were identified. Among those proteins, there were Putative nucleic acid binding protein, glucose-1-phosphate adenylyltransferase (ADP-glucose pyrophosphorylase, AGPase) (EC: 2.7.7.27) large chain, UDP-glucuronic acid decarboxylase, putative calcium-binding protein annexin, putative acetyl-CoA synthetase and putative lipoamide dehydrogenase etc. They were closely associated with metabolism, protein biosynthesis, transcription, signal transduction and so on, all of which are cell activities that are essential to pollen development. Some of the identified proteins, i.e. AGPase, putative lipoamide dehydrogenase and putative acetyl-CoA synthetase were deeply discussed on the relationship to CMS. AGPase catalyzes a very important step in the biosynthesis of alpha 1,4-glucans (glycogen or starch) in bacteria and plants: synthesis of the activated glucosyl donor, ADP-glucose, from glucose-1-phosphate and ATP. The lack of the AGPase in male sterile line might directly result in the reduction of starch, and the synthesis of starch was the most important processes during the development of pollen. In present research, the descent or reduction of putative lipoamide dehydrogenase and putative acetyl-CoA synthetase seemed involved in pollen sterility in rice. The degeneration and formation of various tissues during pollen development may impose high demands for energy and key biosynthetic intermediates. Under such conditions, the TCA cycle needs to operate fully, because the TCA cycle is an important source for many intermediates required for biosynthetic pathways, in addition to performing an oxidative, energy-producing role. Thus, it seemed reasonable to infer that the decrease of putative lipoamide dehydrogenase and putative acetyl-CoA synthetase in anther might prevent the conversion of pyruvate into acetyl-CoA, and as a result, the TCA cycle could no longer operate at a sufficient rate to meet all requirements in anther cells, leading to pollen sterility. This study gave new insights into the mechanism of CMS in rice and demonstrated the power of the proteomic approach in plant biology studies.
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PMID:[Preliminary proteomics analysis of the total proteins of HL Type cytoplasmic male sterility rice anther]. 1655 98

One of the processes by which CheY, the excitatory response regulator of chemotaxis in Escherichia coli, can be activated to generate clockwise flagellar rotation is by acetyl-CoA synthetase (Acs)-mediated acetylation. Deletion of Acs results in defective chemotaxis, indicating the involvement of Acs-mediated acetylation in chemotaxis. To investigate whether Acs is the sole acetylating agent of CheY, we purified the latter from a delta acs mutant. Mass spectrometry analysis revealed that this protein is partially acetylated in spite of the absence of Acs, suggesting that CheY can be post-translationally acetylated in vivo by additional means. Using [14C]AcCoA in the absence of Acs, we demonstrated that one of these means is autoacetylation, with AcCoA serving as an acetyl donor and with a rate similar to that of Acs-mediated acetylation. Biochemical characterization of autoacetylated CheY and mass spectrometry analysis of its tryptic digests revealed that its acetylated lysine residues are those found in CheY acetylated by Acs, but the acetylation-level distribution among the acetylation sites was different. Like CheY acetylated by Acs, autoacetylated CheY could be deacetylated by Acs. Also similarly to the case of Acs-mediated acetylation, the phosphodonors of CheY, CheA and acetyl phosphate, each inhibited the autoacetylation of CheY, whereas the phosphatase of CheY, CheZ, enhanced it. A reduced AcCoA level interfered with chemotaxis to repellents, suggesting that CheY autoacetylation may be involved in chemotaxis of E. coli. Interestingly, this interference was restricted to repellent addition and was not observed with attractant removal, thus endorsing our earlier suggestion that the signaling pathway triggered by repellent addition is not identical to that triggered by attractant removal.
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PMID:The chemotaxis response regulator CheY can catalyze its own acetylation. 1663 Jun 31

Tub is a member of a small gene family, the tubby-like proteins (TULPs), with predominant expression in neurons. Mice carrying a mutation in Tub develop retinal and cochlear degeneration as well as late-onset obesity with insulin resistance. During behavioral and metabolic testing, we found that homozygous C57BL/6J-Tub(tub) mice have a lower respiratory quotient than C57BL/6J controls before the onset of obesity, indicating that tubby homozygotes fail to activate carbohydrate metabolism and instead rely on fat metabolism for energy needs. In concordance with this, tubby mice show higher excretion of ketone bodies and accumulation of glycogen in the liver. Quantitation of liver mRNA levels shows that, during the transition from light to dark period, tubby mice fail to induce glucose-6-phosphate dehydrogenase (G6pdh), the rate-limiting enzyme in the pentose phosphate pathway that normally supplies NADPH for de novo fatty acid synthesis and glutathione reduction. Reduced G6PDH protein levels and enzymatic activity in tubby mice lead accordingly to lower levels of NADPH and reduced glutathione (GSH), respectively. mRNA levels for the lipolytic enzymes acetyl-CoA synthetase and carnitine palmitoyltransferase are increased during the dark cycle and decreased during the light period, and several citric acid cycle genes are dysregulated in tubby mice. Examination of hypothalamic gene expression showed high levels of preproorexin mRNA leading to accumulation of orexin peptide in the lateral hypothalamus. We hypothesize that abnormal hypothalamic orexin expression leads to changes in liver carbohydrate metabolism and may contribute to the moderate obesity observed in tubby mice.
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PMID:Defective carbohydrate metabolism in mice homozygous for the tubby mutation. 1684 32

We report the systematic elaboration of a cost-effective, interference-minimized assay for the label-free optical transduction of chemical reactions. Recently, we have found that certain complexes formed by arginine-rich cell-penetrating peptides (CPPs) and amphiphilic counteranions can act as synergistic anion carriers in lipid bilayer membranes. Application of this discovery to rapid and reversible cytosolic CPP delivery has been described (Futaki, S.; et al. ACS Chem. Biol. 2006, 1, 299). Here, we report the complementary use of polyarginine (pR)-counteranion complexes as general optical transducers of chemical reactions. Counterion screening revealed dodecyl phosphate (DP) as an ideal pR activator. Carboxyfluorescein (CF)-loaded vesicles with a shelf life of 3.5 years served best for the detection of fluorogenic CF release by pR-DP complexes with the naked eye. Inactivation of pR-DP complexes by counterion exchange with hyaluronan (HA) caused no CF emission, while HA removal by hyaluronidase (HAase) did. pR-DP complexes were further compatible with the optical detection of HA immobilization on solid support as well as inhibitor screening for HAase (cromolyn, heparin) with and without substrate immobilization. Controls concerning binary ATP/ADP discrimination for naked-eye kinase detection are mentioned to delineate scope but also limitations of this simple and quite universal method.
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PMID:A cost-effective method for the optical transduction of chemical reactions. Application to hyaluronidase inhibitor screening with polyarginine-counteranion complexes in lipid bilayers. 1698 84


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