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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Campbell, J. J. R. (The University of British Columbia, Vancouver, B.C., Canada), Loretta A. Hogg, and G. A. Strasdine. Enzyme distribution in Pseudomonas aeruginosa. J. Bacteriol. 83:1155-1160. 1962.-Previous studies on the distribution of enzymes in bacteria have indicated that, although individual enzymes were predominantly associated with a particular cellular structure, nevertheless some of the enzyme appeared to be present in all cellular fractions. In the present work with Pseudomonas aeruginosa, it was shown that, in general, an enzyme is present in only one cellular component. Hexokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, gluconic dehydrogenase, malic dehydrogenase, fumarase, isocitric dehydrogenase, isocitritase, and catalase were detected only in the soluble cytoplasm of the cell. Glucose oxidase and succinic dehydrogenase were detected only in the "ghost" fraction. Diphosphopyridine nucleotide oxidase was present in both "ghost" and ribosomal fractions but was most concentrated in the "ghost". Although adenylic kinase was found to be present in all fractions, it was possible to fractionate cells so that almost all of the activity was associated with the soluble cytoplasm a minor amount being associated with the "ghost." Adenosine triphosphatase was most concentrated in the "ghost" but appreciable activity appeared in the cytoplasm. Polynucleotide phosphorylase appeared to be the only enzyme that was convincingly associated with the ribosomes. However, a small amount of activity was associated with the soluble cytoplasm and with the "ghosts."
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PMID:Enzyme distribution in Pseudomonas aeruginosa. 1387 40

In all three kingdoms of life chaperonins assist the folding of a range of newly synthesized proteins. As shown recently, Archaea of the genus Methanosarcina contain both group I (GroEL/GroES) and group II (thermosome) chaperonins in the cytosol. Here we report on a detailed functional analysis of the archaeal GroEL/GroES system of Methanosarcina mazei (Mm) in comparison to its bacterial counterpart from Escherichia coli (Ec). We find that the groESgroEL operon of M. mazei is unable to functionally replace groESgroEL in E. coli. However, the MmGroES protein can largely complement a mutant EcGroES protein in vivo. The ATPase rate of MmGroEL is very low and the dissociation of MmGroES from MmGroEL is 15 times slower than for the EcGroEL/GroES system. This slow ATPase cycle results in a prolonged enclosure time for model substrate proteins, such as rhodanese, in the MmGroEL:GroES folding cage before their release into the medium. Interestingly, optimal functionality of MmGroEL/GroES and its ability to encapsulate larger proteins, such as malate dehydrogenase, requires the presence of ammonium sulfate in vitro. In the absence of ammonium sulfate, malate dehydrogenase fails to be encapsulated by GroES and rather cycles on and off the GroEL trans ring in a non-productive reaction. These results indicate that the archaeal GroEL/GroES system has preserved the basic encapsulation mechanism of bacterial GroEL and suggest that it has adjusted the length of its reaction cycle to the slower growth rates of Archaea. Additionally, the release of only the folded protein from the GroEL/GroES cage may prevent adverse interactions of the GroEL substrates with the thermosome, which is not normally located within the same compartment.
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PMID:Functional characterization of an archaeal GroEL/GroES chaperonin system: significance of substrate encapsulation. 1457 49

Cytochrome c expression and mitochondrial biogenesis can be invoked by elevated intracellular Ca(2+) in muscle cells. To characterize the potential role of Ca(2+) as a messenger involved in mitochondrial biogenesis in muscle, we determined the effects of the Ca(2+) ionophore A-23187 on the expression of nuclear- and mitochondrially encoded genes. Treatment of myotubes with 1 microM A-23187 for 48-96 h increased nuclear-encoded beta-subunit F(1)ATPase and malate dehydrogenase (MDH) mRNA levels by 50-100% (P < 0.05) but decreased mRNA levels of glutamate dehydrogenase (GDH) by 19% (P < 0.05). mRNA levels of the cytochrome c oxidase (COX) nuclear-encoded subunits IV, Vb, and VIc were unchanged, whereas the mitochondrially encoded subunits COX II and COX III were decreased by 30 and 70%, respectively (P < 0.05). This was paralleled by a 20% decrease (P < 0.05) in COX activity. These data suggest that cytoplasmic Ca(2+) differentially regulates the mRNA level of nuclear and mitochondrial genes. The decline in COX II and III mRNA may be mediated by Tfam, because A-23187 modestly reduced Tfam levels by 48 h. A-23187 induced time-dependent increases in Egr-1 mRNA, along with the activation of ERK1/2 and AMP-activated protein kinase. MEK inhibition with PD-98059 attenuated the increase in Egr-1 mRNA. A-23187 also increased Egr-1, serum response factor, and Sp1 protein expression, transcription factors implicated in mitochondrial biogenesis. Egr-1 overexpression increased nuclear-encoded cytochrome c transcriptional activation by 1.5-fold (P < 0.05) and reduced GDH mRNA by 37% (P < 0.05) but had no effect on MDH or beta-subunit F(1)ATPase mRNA. These results indicate that changes in intracellular Ca(2+) can modify mitochondrial phenotype, in part via the involvement of Egr-1.
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PMID:Calcium-regulated changes in mitochondrial phenotype in skeletal muscle cells. 1507 4

The Escherichia coli heat-shock protein ClpB reactivates protein aggregates in cooperation with the DnaK chaperone system. The ClpB N-terminal domain plays an important role in the chaperone activity, but its mechanism remains unknown. In this study, we investigated the effect of the ClpB N-terminal domain on malate dehydrogenase (MDH) refolding. ClpB reduced the yield of MDH refolding by a strong interaction with the intermediate. However, the refolding kinetics was not affected by deletion of the ClpB N-terminal domain (ClpBDeltaN), indicating that MDH refolding was affected by interaction with the N-terminal domain. In addition, the MDH refolding yield increased 50% in the presence of the ClpB N-terminal fragment (ClpBN). Fluorescence polarization analysis showed that this chaperone-like activity is explained best by a weak interaction between ClpBN and the reversible aggregate of MDH. The dissociation constant of ClpBN and the reversible aggregate was estimated as 45 muM from the calculation of the refolding kinetics. Amino acid substitutions at Leu 97 and Leu 110 on the ClpBN surface reduced the chaperone-like activity and the affinity to the substrate. In addition, these residues are involved in stimulation of ATPase activity in ClpB. Thus, Leu 97 and Leu 110 are responsible for the substrate recognition and the regulation of ATP-induced ClpB conformational change.
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PMID:Interaction of the N-terminal domain of Escherichia coli heat-shock protein ClpB and protein aggregates during chaperone activity. 1553 52

A novel ATPase activity that was strongly activated in the presence of either cobalt or manganese ion was discovered in the chaperonin from hyperthermophilic Pyrococcus furiosus (Pfu-cpn). Surprisingly, a significant ADPase activity was also detected under the same conditions. A more extensive search revealed similar nucleotide hydrolysis activities in other thermostable chaperonins. Chaperonin activity, i.e., thermal stabilization and refolding of malate dehydrogenase from the guanidine-hydrochloride unfolded state were also detected for Pfu-cpn under the same conditions. We propose that the novel cobalt/manganese-dependent ATP/ADPase activity may be a common trait of various thermostable chaperonins.
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PMID:A novel ATP/ADP hydrolysis activity of hyperthermostable group II chaperonin in the presence of cobalt or manganese ion. 1634 86

Disease caused by viruses, especially white spot syndrome virus (WSSV), present the greatest challenge to shrimp aquaculture worldwide. Massive tissue disintegration occurs in WSSV-infected ectodermal and mesodermal tissues of penaeid shrimp. The activities of membrane bound phosphatases (Na(+)K(+)ATPase, Ca(2+)ATPase, Mg(2+)ATPase and Total ATPase), transaminases (alanine transaminase (ALT) and aspartate transaminase (AST)) and mitochondrial enzymes (isocitrate dehydrogenase (ICDH), succinate dehydrogenase (SDH), malate dehydrogenase (MDH), alpha-ketoglutarate dehydrogenase (KGDH), NADH dehydrogenase, cytochrome C oxidase) in WSSV-infected tissues (hemolymph, hepatopancreas, gills and muscle) of Fenneropenaeus indicus were determined at intervals after WSSV infection (0, 24, 48, 72 and after 72 h (moribund)). The activities of phosphatases, transaminases and mitochondrial enzymes in healthy as compared with WSSV-infected hemolymph, hepatopancreas, gills and muscle showed marked divergence throughout the course of infection. WSSV infected hemolymph, hepatopancreas, gills and muscle exhibited significantly reduced activity of membrane bound phosphatases compared with the uninfected animals. Inactivation of these enzymes may occur due to increased production of free radicals, that cause conformational change by oxidation of 'SH' groups present at the active site. Significantly marked elevation in the activities of transaminases (ALT and AST) was observed in WSSV-infected hemolymph, hepatopancreas, gills and muscle compared to the uninfected tissues. This may be due to leakage of these enzymes from the damaged tissues. The activities of mitochondrial enzymes in WSSV-infected tissues were significantly decreased compared to the activities in uninfected animals. WSSV-infected animals showed reduced feeding that may have led to decreased oxidation of glucose via the TCA cycle. Excessive production of free radicals in WSSV-infected animals may have affected aerobic oxidation leading to lower production of ATP. It is concluded that membrane dynamics play a major role in the pathogenesis of WSSV infection.
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PMID:Activities of membrane bound phosphatases, transaminases and mitochondrial enzymes in white spot syndrome virus infected tissues of Fenneropenaeus indicus. 1641 26

Transfer of Euglena gracilis Klebs Z cells from phototrophic to organotrophic growth on acetate results in derepression of the key enzymes of the glyoxylate cycle, malate synthase and isocitrate lyase, which appear coordinately regulated. The derepression of malate synthase and isocitrate lyase was accompanied by increased specific activities of succinate dehydrogenase, fumarase, and malate dehydrogenase, but hydroxypyruvate reductase activity was unaltered.Isolation of organelles from broken cell suspensions of cells grown heterotrophically on acetate was achieved by isopycnic centrifugation on sucrose gradients. Peaks of mitochondrial enzymes were obtained at equilibrium densities of 1.22 g cm(3) and 1.16 g cm(3), and although significant differences in the distribution of tricarboxylic acid cycle enzymes between these two peaks were not recorded adenosine triphosphatase activity was detected only in the less dense fraction (1.16 g cm(3)) showing this contained damaged mitochondria. The peak of particulate glyoxylate cycle enzymes was at an equilibrium density of 1.25 g cm(3), this being the same as that for glycolate pathway enzymes from phototrophic cells. Citrate synthase, isocitrate lyase, malate synthase, and malate dehydrogenase were all present in this fraction so it was concluded that Euglena glyoxysomes contain a complete glyoxylate cycle.
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PMID:Microbody-marker Enzymes during Transition from Phototrophic to Organotrophic Growth in Euglena. 1665 2

Protoplasts from suspension-cultured cells of Nicotiana glutinosa L. were lysed in 0.3 molar sorbitol in 2 millimolar ethylenediaminetetraacetate-tris(hydroxymethyl) aminomethane (pH 7.5) to release intact vacuoles. The vacuoles were purified by centrifugation in a Ficoll step gradient. About 11% of the vacuoles and 13% of the acid phosphatase activity was recovered in the purified vacuole fraction, suggesting that the vacuole is the major site for acid phosphatase in these cells. NADH-cytochrome c reductase, malate dehydrogenase, and cytochrome c oxidase activities were reduced during vacuole purification. The majority of the adenosine 5'-triphosphate (ATP) hydrolytic activity of purified vacuoles was associated with nonspecific acid phosphatase and not with a transport ATPase. As judged by acid phosphatase distribution and electron microscopy, the effective density of vacuoles in a sucrose gradient was low (less than 1.1 grams per cubic centimeter), although an unequivocal estimate of the vacuole or tonoplast density was not possible from the experiments conducted.
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PMID:Isolation and partial characterization of vacuoles from tobacco protoplasts. 1666 Nov 3

Heparin and quercetin induce capacitation in spermatozoa through membrane receptor binding and inhibition of Ca-ATPase of the plasma membrane, respectively. Although capacitation is energy intensive, ammonia from amino acid metabolism can inhibit respiration and Krebs cycle activity. The objective was to determine activities of key enzymes in bull spermatozoa that contribute to the redox state and supply energy for capacitation. Malate dehydrogenase (MDH-NAD(+)), alanine and aspartate aminotransferases (ALT, AST), and lactate dehydrogenase-X (LDH-X) were measured spectrophotometrically (340 nm); mean (+/-S.D.) activities in control spermatozoa were 7.65+/-1.67, 0.45+/-0.05 and 0.74+/-0.14x10(-2)U/10(8) spermatozoa for MDH-NAD(+), ALT and AST, respectively, and were 2.83+/-0.66U/10(8) spermatozoa for LDH-X. Heparin decreased (P<0.05) activities of MDH-NAD(+), ALT, AST and LDH-X (78, 53, 66 and 66% of control levels, respectively); we inferred that amino acid catabolism was decreased. Quercetin decreased (P<0.05) activities of MDH-NAD(+) and ALT (60 and 49% of control levels), but activities of AST and LDH-X were not significantly different from controls; apparently maintenance of LDH-X activity supplied pyruvate for cellular metabolism. The proportion of capacitated spermatozoa in controls (8.5+/-1.73%) was substantially increased (P<0.05) by treatment with either heparin (36.2+/-4.5%) or quercetin (32.8+/-4.7%), there was no significant difference among groups for acrosomal integrity and sperm viability. In conclusion, heparin- or quercetin-induced capacitation affected different metabolic pathways that modulated the redox state and oxidative metabolism in cryopreserved bovine spermatozoa.
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PMID:Heparin and quercitin generate differential metabolic pathways that involve aminotransferases and LDH-X dehydrogenase in cryopreserved bovine spermatozoa. 1708 43

Folding of substrate proteins inside the sequestered and hydrophilic GroEL-GroES cis cavity favors production of the native state. Recent studies of GroEL molecules containing volume-occupying multiplications of the flexible C-terminal tail segments have been interpreted to indicate that close confinement of substrate proteins in the cavity optimizes the rate of folding: the rate of folding of a larger protein, Rubisco (51 kDa), was compromised by multiplication, whereas that of a smaller protein, rhodanese (33 kDa), was increased by tail duplication. Here, we report that this latter effect does not extend to the subunit of malate dehydrogenase (MDH), also 33 kDa. In addition, single-ring versions of tail-duplicated and triplicated molecules, comprising stable cis complexes, did not produce any acceleration of folding of rhodanese or MDH, nor did they show significant retardation of the folding of Rubisco. Tail quadruplication produced major reduction in recovery of native protein with both systems, the result of strongly reduced binding of all three substrates. When steady-state ATPase of the tail-multiplied double-ring GroELs was examined, it scaled directly with the number of tail segments, with more than double the normal ATPase rate upon tail triplication. As previously observed, disturbance of ATPase activity of the cycling double-ring system, and thus of "dwell time" for the folding protein in the cis cavity, produces effects on folding rates. We conclude that, within the limits of the approximately 10% decrease of cavity volume produced by tail triplication, there does not appear to be an effect of "close confinement" on folding in the cis cavity.
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PMID:Perturbed ATPase activity and not "close confinement" of substrate in the cis cavity affects rates of folding by tail-multiplied GroEL. 1737 95


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