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)

Incubation of African green monkey kidney (BS-C-1) cells and mouse fibroblasts (3T6) in the presence of adenosine for 4 hours resulted in increases in the nuclear compartment pools of adenosine 5'-triphosphate (ATP) and nuclear ATP/adenosine 5'-diphosphate (ADP) ratios. Adenine and inosine, which yield increases in total cellular ATP pools and ATP/ADP ratios similar to those promoted by adenosine, do not produce similar increases in the nuclear compartment. Adenosine-promoted increases in nuclear ATP pools were higher in the untransformed, serially propagated, BS-C-1 cells than in the spontaneously transformed 3T6 cells. Adenosine-promoted compartmentalized ATP pools in primary chick embryo fibroblasts were reduced upon transformation of these cells with Rous sarcoma virus, resulting in free mixing of all of the ATP pools synthesized from various salvage precursors. The growth regulatory properties of the nuclear compartment pools of adenine nucleotides is suggested by the big increases in nuclear ATPase and adenosine 5'-monophosphate (AMP) deaminase activities upon the entry of 3T6 cells into the S phase of their cycle. These enzymatic activities would tend to lower the nuclear ATP/ADP ratios and reduce the total adenine nucleotide pools in these nuclei respectively--conditions which were shown by earlier in vitro studies to be favorable to DNA replication.
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PMID:Compartmentalized ATP pools produced from adenosine are nuclear pools. 645 Jul 72

Electron microscopy cytochemistry has been used to study the cytoplasmic location of liposomes and lipid vesicles following specific antibody-dependent phagocytosis. The vesicle compositions were 94-99 mol% 'fluid' lipid (egg phosphatidylcholine or dimyristoylphosphatidylcholine at 37 degrees C or 'solid' lipid (dipalmitoylphosphatidylcholine at 37 degrees C). In some cases, 4 mol% phosphatidylserine was included in the vesicle membrane so as to vary the surface charge density. These vesicles undergo specific antibody-dependent phagocytosis by RAW264 macrophages when the lipid membranes contain 1-2 mol% dinitrophenyl lipid hapten in the presence of rabbit anti-dinitrophenyl IgG antibody. Internalized lipid vesicles can be visualized with the electron microscope when ferritin is trapped in the internal aqueous compartments prior to internalization. The lipid vesicles were demonstrated to be internal to the macrophage plasma membranes by selectively staining the plasma membranes with Ruthenium red. The cytoplasmic location of vesicles and liposomes was studied by electron microscopic staining for activities of the following enzymes: (1) acid phosphatase; (2) inorganic trimetaphosphatase; (3) adenosine triphosphatase; and (4) glucose-6-phosphatase. The first two enzymatic activities were found in association with ferritin-containing vesicles after antibody-dependent phagocytosis, showing the formation of vesicle-containing phagolysosomes. Adenosine triphosphatase and glucose-6-phosphatase were primary not associated with the vesicles, suggesting a minimal association of vesicles with plasma membrane, Golgi, endoplasmic reticulum and perinuclear cisternae. Phagosome-lysosome fusion did not appear to depend on the type of target lipid vesicle or liposome, on the 'fluidity' of the target membrane, or the presence of phosphatidylserine in the target membrane.
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PMID:Cytochemical study of liposome and lipid vesicle phagocytosis. 668 37

Synaptic vesicles isolated from bovine cerebral cortex were found to contain alkaline phosphatase activity towards p-nitrophenylphosphate and alpha-naphthyl phosphate, but not towards pyridoxal phosphate. The enzyme had an apparent molecular weight of 125,000 and co-purified with the synaptic vesicles in parallel with the specific neurotransmitter content and with the loss of contaminating components, whereas the major phosphatase which was present in the brain homogenate, with an apparent molecular weight of 140,000 purified away. The optimal pH for the enzyme activity on p-nitrophenylphosphate was 9.8. At this pH the activity was 33.4 nmol/mg protein/min, and the apparent Km value was 0.31 +/- 0.05 mM. The pH dependency of the synaptic vesicle phosphatase activity towards p-nitrophenylphosphate differed from that of the Ca2+/Mg2+-dependentt ATP hydrolysis by the synaptic vesicles. Upon mild digestion of lyzed vesicles with trypsin, phosphatase activity was reduced whereas the ATPase activity was retained suggesting that the phosphatase and the ATPase are two different enzymes. The phosphatase was reversibly inhibited by ethyleneglycol bis (aminoethyl ether) N,N'-tetracetic acid (EGTA) and activity was restored by the addition of an equimolar amount of CA2+. Magnesium ions could restore only 30% of the activity. The activity of the synaptic vesicle phosphatase was not affected by o-phenanthroline, zinc ion or by cAMP. Tetranitromethane inactivated the enzyme irreversibly, whereas phenylmethanesulfonylfluoride diisopropylfluorophosphate and p-hydroxymercurybenzoate inhibited the activity partially. The enzyme did not have a diesterase activity. Adenosine mono-, di- and triphosphate inhibited the p-nitrophenylphosphatase activity and were also hydrolyzed by the vesicle preparation. However, the different kinetic parameters obtained with the nucleotide as inhibitors or as substrates suggest that additional enzymes are involved in the hydrolysis of the adenine nucleotides in vesicle preparation.
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PMID:A calcium-stimulated alkaline phosphatase associated with synaptic vesicles. 741 49

The heat shock protein GroEL from Escherichia coli is a tetradecameric oligomer that facilitates the refolding of nonnative polypeptides in an ATP-hydrolysis dependent reaction. A mutant in GroEL was prepared in which lysine 3 was substituted with glutamate, which destabilizes the oligomeric structure of GroEL (Horovitz, A., Bochkareva, E.S., and Girshovich, A.S. (1993) J. Biol. Chem. 268, 9957-9959). The highly expressed and purified GroELK3E was judged to be monomeric by sedimentation equilibrium, yielding a molecular weight of 54,500, despite a weak tendency of the mutant to reversibly form higher order aggregates above 4 mg ml-1. The monomeric variant appears to be folded based on the far UV circular dichroism spectrum, which shows significant alpha-helical content, but with slight differences in conformation relative to wild-type GroEL. The increase in exposed hydrophobic surface of the monomer was probed with the dye 4,4'-bis-1-anilino-3-naphthalenesulfonate (bis-ANS). The fluorescence of bis-ANS increases approximately 150-fold in the presence of the mutant, and about 4 mol of bis-ANS bind per mol of monomer, with a binding constant of 1.6 microM. Adenosine nucleotide binding to monomeric GroELK3E resulted in considerable quenching of bis-ANS fluorescence, correlating with significant structural changes as seen in the far UV circular dichroism, and permitted the measurement of binding isotherms for ATP and ADP. Hyperbolic ATP binding isotherms yield a dissociation constant of 82 microM, about 4-fold weaker than the K0.5 for ATP seen in steady-state kinetics assays of the wild-type GroEL ATPase.A similar difference was seen for ADP binding. These results suggest that the mutation disrupts the native tetradecameric quaternary structure through conformational changes that may also weaken nucleotide binding. The monomeric mutant exhibited no chaperone activity as evidenced by a filure to inhibit or facilitate the refolding of chemically denatured enolase, an inability to refold denatured rhodanese above spontaneous levels, and a lack of binding to alpha-casein, a competitor in many chaperonin-promoted refolding reactions. Thus, the formation of assembly incompetent monomers by the lysine 3 to glutamate mutation results in a dramatic decrease in the affinity for nonnative polypeptide chains and suggests that the oligomeric nature of GroEL is crucial for its molecular chaperone function.
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PMID:A monomeric variant of GroEL binds nucleotides but is inactive as a molecular chaperone. 765 15

The histochemical profiles of the bulbospongiosus (BS) and ischiocavernosus (IC) muscles were investigated on autopsy samples obtained from 13 men aged 18 to 33. Adenosine triphosphatase (ATPase) reactions were used for differentiation of muscle fibres into type 1 (slow twitch, tonic), and type 2 (fast twitch, phasic) and subtypes 2A, 2B, 2C. The activity of oxidative and glycolytic enzymes was also assayed. Because the percentage and diameters of both fibre types varied considerably in different areas of the same muscle, two methods of counting were applied and at least two fields of each sample were evaluated. The mean percentage of type 1 fibres in BS muscles was 34.8% and 23.2%, that in IC muscles 49.7% and 39.7%. The mean diameter of type 1 fibres was 31.0 microns (BS) and 26.2 microns (IC), that of type 2 fibres ranged from 30.0 microns (BS) to 36.6 microns (IC). The comparison of BS and IC muscles with other nonskeletal voluntary muscles revealed that BS and IC muscles are similar to the striated sphincters, particularly with regard to the numerical distribution of fibre types and fibre diameters.
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PMID:Histochemical characteristics of bulbospongiosus and ischiocavernosus muscles in man. 768 49

1. The effects of dextrose, magnesium (Mg) and adenosine on membrane potential and force of contraction were studied in driven and overdriven canine cardiac Purkinje tissue. 2. Dextrose (50 mmol/L) and adenosine (4-6 mmol/L) both showed protective action (the latter to a lesser extent) against simulated anoxia and reperfusion-induced arrhythmias, increased force of contraction transiently on reperfusion, and the former sustained the increase in force to a lower level as long as it was in the superfusing solution. 3. Dextrose (50 mmol/L) and Mg (5 mmol/L) restored overdrive-induced hyperpolarization during simulated anoxia. Adenosine was largely ineffective. 4. It was concluded that dextrose and adenosine (to a lesser extent) protect against arrhythmias by replenishing the critical intracellular pool of ATP which controls membrane transport of electrolytes such as K and Ca. Restoration of Na-K ATPase activity alone (as in the case of high Mg concentrations) is not sufficient to prevent arrhythmias.
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PMID:Dextrose-, adenosine- and magnesium-induced protective actions during anoxia and reperfusion in canine Purkinje tissue. 781 22

The enhancer-binding protein NIFA is required for transcriptional activation of nif promoters by the alternative holoenzyme form of RNA polymerase, which contains the sigma factor sigma 54 (sigma N). NIFA hydrolyzes nucleoside triphosphates to catalyze the isomerization of closed promoter complexes to transcriptionally competent open complexes. The activity of NIFA is antagonized by the regulatory protein NIFL in response to oxygen and fixed nitrogen in vivo. We have investigated the requirement for nucleotides in the formation and stability of open promoter complexes by NIFA and inhibition of its activity by NIFL at the Klebsiella pneumoniae nifH promoter. Open complexes formed by sigma 54-containing RNA polymerase are considerably more stable to heparin challenge in the presence of GTP than in the presence of ATP. This differential stability is most probably a consequence of GTP being the initiating nucleotide at this promoter. Adenosine nucleosides are specifically required for Azotobacter vinelandii NIFL to inhibit open complex formation by native NIFA, and the nucleoside triphosphatase activity of NIFA is strongly inhibited by NIFL under these conditions. We propose a model in which NIFL modulates the activity of NIFA via an adenosine nucleotide switch.
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PMID:Transcriptional activation of the nitrogenase promoter in vitro: adenosine nucleotides are required for inhibition of NIFA activity by NIFL. 786 90

In order to investigate the activity of certain enzymes [Alkaline phosphatase (ALP), Acid phosphatase (ACP), Adenosine triphosphatase (ATPase), 5'-Nucleotidase (5'-N)] in the proximal epiphysis of the humerus, tissue specimens were obtained from pregnant rats on the 15th, 17th, 19th and 20th days of gestation and on the 1st, 10th, 20th, 30th, 40th and 60th days of postnatal development. Enzymatic activity in the chondral ossification, in the perichondral areas of the epiphysis, was first seen on the 15th day of gestation. ALP and ATPase could also be observed for the first time in fetuses aged 15 days, whereas ACP and 5'-N could not be detected. These latter enzymes were observed for the first time in the proximal humeral epiphysis of fetuses aged 17 days. ALP, a marker for hypertrophic and calcifying cartilage, was observed extensively in the central hypertrophic part of the cartilaginous perichondral zones, which showed calcification during the development of the epiphysis. ALP, ATP and 5'-N activity was very marked in the cytoplasm of osteoblasts and in the periosteal matrix, but strong ACP activity was found in the cells of the chondrolysis zone. In conclusion; according to our observations, heterogeneity of the proximal epiphysis of the humerus exhibits intrinsic differences between the cells of different zones. The activity of all enzymes showed an increase according to the developmental age. This suggests that all of these enzymes play a role during developmental ossification.
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PMID:A histochemical study on the enzymatic activity in the proximal epiphysis of the humerus during the prenatal and postnatal periods in rats. 787 99

The action on left ventricular function of Astragalus Membranaceus (AM), a Qi-tonic, in 20 patients with angina pectoris was studied by means of Doppler Echocardiogram (DEC). It showed that cardiac output increased from 5.09 +/- 0.21 to 5.95 +/- 0.18 L/min 2 weeks after AM was administered (P < 0.01), and no improvement of left ventricular diastolic function appeared. Adenosine triphosphatase activity was not inhibited by using AM, which was different from that of digitalis.
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PMID:[Action of Astragalus membranaceus on left ventricular function of angina pectoris]. 795 Jan 92

Histochemical techniques were employed to study the tissue distribution of hydrolytic enzymes in adult female Onchocerca fasciata (Filarioidea: Onchocercidae). Different tissues differed considerably in the localization and distribution of the six enzymes studied. Acid phosphatase (AcPase) activity was detected in the cuticle, hypodermis and reproductive organs. Alkaline phosphatase (AlkPase) activity was largely absent. Adenosine triphosphatase (ATPase) was found in the somatic musculature and muscles of the uterine ducts, whereas 5'-nucleotidase (5'-Nu) was restricted to young oocytes and dividing embryos in the female worm. Strong glucose-6-phosphatase (G-6-Pase) activity was demonstrated in the uterine epithelial cells and microfilariae, as was weak activity in the hypodermis. Naphthylamidase (NAM) activity was detected in the hypodermis, with lower activity occurring in the somatic musculature. The possible functions of these enzymes are discussed with respect to their location. The hydrolytic enzymes AcPase and NAM in the body wall are probably involved in absorptive-digestive functions, NAM in the somatic musculature may be concerned with tissue protein turnover, and ATPase, 5'-Nu and G-6-Pase may have a role in active transport and energy metabolism.
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PMID:Histochemical distribution of hydrolytic enzymes in adult Onchocerca fasciata (Filarioidea: Onchocercidae). 803 35


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