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:3.6.3.14 (ATP synthase)
7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To clarify the damage site of complicated oxidative phosphorylation function after hemorrhagic shock in jaundiced liver mitochondria, the proton adenosine triphosphatase complex (H(+)-ATPase) activity of inside-out submitochondrial particles, mitochondrial membrane potential, and oxygen consumption in the presence of uncoupler were studied as indices of phosphorylation, membrane intactness, and oxidation, respectively. Hemorrhagic shock was induced according to the Wiggers' model (mean arterial blood pressure = 40 mm Hg) in rats made jaundiced by common bile duct ligation; rats that had undergone sham operations served as controls. After reinfusion of the shed blood, all of the control rats survived, but all of the jaundiced rats died. Liver mitochondria from jaundiced rats after 1 hour of hypotension demonstrated a 48% decrease in mitochondrial ATPase activity without remarkable changes in either oxidative activity or membrane potential of liver mitochondria. The reduction of ATPase activity appeared to be due to its release in the supernatants obtained from submitochondrial particles, because the ATPase activity of supernatants in jaundiced rats was significantly (p less than 0.001) higher than that of the controls. It is suggested that this enzyme plays a key role in energy restoration in recovery from shock.
...
PMID:Alterations in the proton ATPase activity of rat liver mitochondria after hemorrhagic shock. 138 75

HL60 cells isolated for resistance to vincristine (HL60/Vinc cells) or doxorubicin (HL60/Adr cells) contain enhanced levels of an energy-dependent drug efflux pump. HL60/Vinc cells contain the drug transporter P-glycoprotein, whereas the HL60/Adr isolate does not. In the present study, we examined the possible involvement of vacuolar H(+)-adenosine triphosphatase (H(+)-ATPase) activity in drug resistance in HL60 cells. We utilized bafilomycin A1, an agent which selectively inhibits vacuolar H(+)-ATPase activity at low concentrations. The results showed that bafilomycin A1 induced a major increase in drug accumulation and inhibited drug efflux in both HL60/Adr cells and HL60/Vinc cells. Similar results were obtained with 7-chloro-4-nitrobenz-2-oxa 1,3 diazole, an agent which is also capable of inhibiting vacuolar H(+)-ATPase. Azide, an inhibitor of F1F0 mitochondrial ATPase, and vanadate and ouabain, which are inhibitors of E1E2-type ATPase, did not affect drug levels in resistant cells. We also observed that bafilomycin A1 did not compete with [3H]azidopine binding to P-glycoprotein. Thus, bafilomycin A1 does not appear to function as a substrate for P-glycoprotein. These results suggest an involvement of vacuolar H(+)-ATPase activity in the pathway of drug efflux from HL60/Adr cells and HL60/Vinc cells. The mechanism of this action remains to be determined.
...
PMID:Involvement of vacuolar H(+)-adenosine triphosphatase activity in multidrug resistance in HL60 cells. 183 9

The effects of three tetrachlorobiphenylols [2',3',4',5'-tetrachloro-2-biphenylol (1); 2',3',4',5'-tetrachloro-4- biphenylol (2); and 2',3',4',5'-tetrachloro-3-biphenylol (3)]; three monochlorobiphenylols [5-chloro-2-biphenylol (5), 3-chloro-2-biphenylol (6); and 2-chloro-4-biphenylol (7)] and a tetrachlorobiphenyldiol [3,3',5,5'-tetrachloro-4,4'-biphenyldiol (4) on respiration, adenosine triphosphatase (ATPase) activity, and swelling in isolated mouse liver mitochondria have been investigated. Tetrachlorobiphenylols (1-3) and the tetrachlorobiphenyldiol (4) inhibited state-3 respiration in a concentration-dependent manner with succinate as substrate (flavin adenine dinucleotide [FAD]-linked) and the tetrachlorobiphenyldiol (4) caused a more pronounced inhibitory effect on state-3 respiration than the other congeners. The monochlorobiphenylols 5-7 were less active as inhibitors of state-3 mitochondrial respiration and significant effects were observed only at higher concentration (greater than or equal to 0.4 microM). However, in the presence of the nicotinamide adenine dinucleotide (NAD)-linked substrates (glutamate plus malate), hydroxylated PCBs (1-7) significantly inhibited mitochondrial state-3 respiration in a concentration-dependent manner. Compounds 5, 6, and 7 uncoupled mitochondrial oxidative phosphorylation only in the presence of FAD-linked substrate as evidenced by increased oxygen consumption during state-4 respiratory transition, stimulating ATPase activity, releasing oligomycin-inhibited respiration, and inducing mitochondrial swelling (5, 6, and 7). Tetrachlorobiphenylols 1, 2, and 3 had no effect on mitochondrial ATPase activity while the tetrachlorobiphenyldiol, 4, decreased the enzyme activity. The possible inhibitory site of electron transport by these compounds and their toxicologic significance is discussed.
...
PMID:Effects of hydroxylated polychlorinated biphenyls on mouse liver mitochondrial oxidative phosphorylation. 183 67

Oxyphil cells are characterized by cytoplasm packed with large numbers of mitochondria. Study of these unusual cells may provide information about the regulation of mitochondrial biogenesis. Although it has been suggested that this is a compensatory proliferation due to a mitochondrial dysfunction, no such dysfunction has been well documented. In this study we considered the possibility of dysfunction in the mitochondrial enzyme F1/Fo-adenosine triphosphatase(ATPase) as a stimulating factor involved in the mitochondrial proliferation of oxyphil cells. Mitochondria isolated from frozen tissue of a renal oncocytoma showing structural integrity and purity by electron microscopy were studied. Submitochondrial particles formed by sonic disruption showed the presence of the F1 component of mitochondrial ATPase with electron microscopy which was functionally active. The oligomycinsensitive ATPase activity from the renal oncocytoma was 0.133 mumol/min.mg submitochondrial particle protein which was higher than the readings obtained from normal kidney tissue (0.091 mumol/min.mg SMP protein) obtained from hamsters. Normal human renal tissue obtained at autopsy contained only nonfunctional mitochondria and therefore could not be used as control tissue. Mitochondrial ATPase dysfunction does not appear to be the inciting factor in the proliferation of mitochondria seen in oxyphil cell metaplasia and future studies should consider other possibilities. Preliminary functional studies of this nature can be performed with properly prepared frozen surgical tissue.
...
PMID:Mitochondrial adenosine triphosphatase in the oxyphil cells of a renal oncocytoma. 213 85

This study was designed to determine: (1) the myocardial adenosine triphosphatase (ATPase) activities of normal humans and patients with dilated cardiomyopathy and (2) whether ATPase activity is related to age, cause and severity of heart failure, and digitalis therapy. Endomyocardial biopsies were performed in 32 subjects. Results from six were normal. Ventricular failure in the other 26 was idiopathic (n = 15), familial (n = 3), alcohol induced (n = 5), or related to doxorubicin therapy (n = 3). The biopsies were analyzed for total, mitochondrial, Na+-K+, Ca++, and Mg++ ATPase activities. Total and mitochondrial ATPase activities correlated with left ventricular ejection fraction (r = 0.65 and 0.67, respectively; both p = 0.0001). Residual Mg++ ATPase activity correlated weakly with ventricular function as measured by echocardiography (p = 0.05). Na+-K+ ATPase activity was depressed in patients receiving digitalis (p = 0.01). These results suggest that progressive ventricular dysfunction may be associated with a progressive loss of total ATPase, mitochondrial ATPase and, to a lesser extent, Mg++ ATPase activity. Although depressed mitochondrial ATPase activity is not likely to be the primary cause of ventricular dysfunction, it could perpetuate failure by leading to inadequate production of adenosine triphosphate. Further study of ATPase activities may provide additional insight into the pathogenesis of cardiac failure.
...
PMID:Human myocardial adenosine triphosphatase activities in health and heart failure. 282 53

A mutant strain of Escherichia coli was isolated in which Gly-48 of the mature epsilon-subunit of the energy-transducing adenosine triphosphatase was replaced by Asp. This amino acid substitution caused inhibition of ATPase activity (about 70%), loss of ATP-dependent proton translocation and lowered oxidative phosphorylation, but did not affect proton translocation through the F0. Purified F1-ATPase from the mutant strain bound to stripped membranes with the same affinity as the normal F1-ATPase. Partial revertant strains were isolated in which Pro-47 of the epsilon-subunit was replaced by Ser or Thr. Pro-47 and Gly-48 are predicted to be residues 2 and 3 in a Type II beta-turn and the Gly-48 to Asp substitution is predicted to cause a change from a Type II to a Type I or III beta-turn. Space-filling models of the beta-turn (residues 46-49) in the normal, mutant and partial revertant epsilon-subunits indicate that the peptide oxygen between Pro-47 and Gly-48 is in a different position to the peptide oxygen between Pro-47 and Asp-48 and that the substitution of Pro-47 by either Ser or Thr restores an oxygen close to the original position. It is suggested that the peptide oxygen between Pro-47 and Gly-48 of the epsilon-subunit is involved either structurally in inter-subunit H-bonding or directly in proton movements through the F1-ATPase.
...
PMID:Amino acid substitutions in the epsilon-subunit of the F1F0-ATPase of Escherichia coli. 287 66

Thermoacidophilic archaebacteria have gained much interest because of their phylogenetic distance to eubacteria and eukaryotes and also because of their unique living conditions. Investigation of the energy-converting system therefore offers a key for understanding the evolutionary position and environmental adaptation of these unusual bacteria. A plasma-membrane-associated adenosine triphosphatase with specific activities of 0.3-0.6 mumol min-1 (mg protein)-1 has been detected in the thermoacidophilic archaebacterium Sulfolobus acidocaldarius (DSM 639). The enzyme exhibits two optima at pH 5.5 and 8.0, sulfite activation leads to only one optimum at pH 6.25. In the presence of the divalent cations Mg2+ or Mn2+ it hydrolyzes ATP with highest reactivity and also other purine and pyrimidine nucleotides, but not ADP and pyrophosphate. A specific stimulation by monovalent cations is not observed. The ATPase activity is not inhibited by N,N'-dicyclohexylcarbodiimide, azide or vanadate, but it is by the vascular ATPase inhibitor nitrate with an [I]50 of 8 mM. Linear Arrhenius plots up to 75 degrees C reflect pronounced adaptation to the hot environment of the archaebacterium. The solubilized ATPase as localized by activity staining in non-denaturating gels and further analyzed by sodium dodecyl sulfate electrophoresis is composed of two major polypeptides of 65 and 51 kDa reminiscent of the alpha and beta subunits of eubacterial and eukaryotic F0F1-ATPases. The ATPase is suggested as a probable candidate for a reversibly acting ATP synthase responsible for oxidative phosphorylation found in Sulfolobus acidocaldarius.
...
PMID:A plasma-membrane associated ATPase from the thermoacidophilic archaebacterium Sulfolobus acidocaldarius. 295 1

HeLa cells in a monolayer culture were synchronized to S, G2 and mitotic phases by use of excess (2.5 mM) deoxythymidine double-block technique. The localizations of Ca2++-activated adenosine triphosphatase (ATPase) at different phases of the cell cycle were studied using light- and electron-microscopic histochemical techniques, and microphotometric comparisons of the densities of reaction products. Enzyme reaction product was always localized in the endoplasmic reticulum, nuclear membrane, mitochondria and Golgi apparatus, but there were qualitative and quantitative differences related to the phases of the cell cycle. In S phase the activity was mainly concentrated in a perinuclear area of the cytoplasm whereas in G2 and mitosis the activity was scattered throughout the cell. The total activity per cell was maximal in G2, was less in S phase and least in mitosis. Activity in the mitochondria and endoplasmic reticulum was distinctly less in mitosis than in other phases of the cell cycle. The mitochondrial ATPase differed from the ATPase at other sites in ion dependence and sensitivity to oligomycin. The results suggest that there may be several distinct ATPases in proliferating cells.
...
PMID:Ultrastructural localization of adenosine triphosphatase activity in HeLa cells at various stages of the cell cycle. 296 37

Extraction with 0 04% (w/v) Triton X-100 removes the flagellar membrane from sea urchin sperm while leaving the motile apparatus apparently intact When reactivated in a suitable medium containing exogenous adenosine triphosphate (ATP), nearly 100% of the sperm are motile and they swim in a manner resembling that of live sperm. Under standard conditions, with 1 mM ATP at 25 degrees C, the reactivated sperm had an average frequency of 32 beats/sec and progressed forward a distance of 2.4 microm/beat; comparable figures for live sperm in seawater were 46 beats/sec and 3 9 microm/beat. The adenosine triphosphatase (ATPase) activity of the reactivated sperm was measured with a pH-stat in the presence of oligomycin to inhibit residual mitochondrial ATPase. The motile sperm had an ATPase activity of 0.16 micromole P(i)/(min x mg protein), while sperm that had been rendered non-motile by homogenizing had an activity of 0 045 micromole P(i)/(min x mg protein). The difference between the ATPase activities of the motile and nonmotile sperm was tentatively interpreted as the amount of activity coupled to movement, and under optimal conditions it amounted to about 72% of the total ATPase activity Under some conditions the movement-coupled ATPase activity was proportional to the beat frequency, but it was possibly also affected by other wave parameters. The coupled ATPase activity decreased to almost zero when movement was prevented by raising the viscosity, or by changing the pH or salt concentration. The motility of reactivated sperm was wholly dependent on the presence of ATP; other nucleotides gave very low phosphatase activity and no movement. The requirement for a divalent cation was best satisfied with Mg(++), although some motility was also obtained with Mn(++) and Ca(++). The coupled ATPase activity had a Michaelis constant (K(m)) of 0.15 mM. The beat frequency of the reactivated sperm varied with the ATP concentration, with an effective "K(m)" of 0.2 mM.
...
PMID:Flagellar movement and adenosine triphosphatase activity in sea urchin sperm extracted with triton X-100. 426 Oct 39

Accumulation of calcium in the mitochondria of rat liver parenchymal cells at 16 and 24 hours after poisoning with carbon tetrachloride is associated with an increase in amount of liver inorganic phosphate, the persistence of mitochondrial adenosine triphosphatase activity, and the formation of electron-opaque intramitochondrial masses in cells with increased calcium contents. These masses, which form within the mitochondrial matrix adjacent to internal mitochondrial membranes, resemble those observed in isolated mitochondria which accumulate calcium and inorganic phosphate; are present in a locus similar to that of electron opacities which result from electron-histochemical determination of mitochondrial ATPase activity; and differ in both appearance and position from matrix granules of normal mitochondria. After poisoning, normal matrix granules disappear from mitochondria prior to their accumulation of calcium. As calcium-associated electron-opaque intramitochondrial masses increase in size, mitochondria degenerate in appearance. At the same time, cytoplasmic membrane systems of mid-zonal and centrilobular cells are disrupted by degranulation of the rough endoplasmic reticulum and the formation of labyrinthine tubular aggregates. The increase in amount of inorganic phosphate in rat liver following poisoning is balanced by a decreased amount of phosphoprotein. These chemical events do not appear to be related, however, as the inorganic phosphate accumulated is derived from serum inorganic phosphate.
...
PMID:Liver parenchymal cell injury. 3. The nature of calcium--associated electron-opaque masses in rat liver mitochondria following poisoning with carbon tetrachloride. 428 48


<< Previous 1 2 3 4 5 6 Next >>

---