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

The effects of aldosterone on protein synthesis in the latent period were investigated on cultured renal collecting duct cells from neonatal rabbit kidneys. Tissue was incubated with radioactively labelled uridine and amino acids and then precipitated with trichloroacetic acid in order to determine the intracellular precursor pool and identify new synthesis of RNA and protein. During the latent period, aldosterone increased the intracellular radioactive uridine pool and total radioactive RNA content already 20 and 60 min after its application; conversely 40 min after aldosterone introduction, no stimulation was found. Further experiments revealed that the intracellular radioactive amino acid pool was generally increased by aldosterone after 20, 40 and 60 min, while a distinct increased radioactive protein content was found to be induced by aldosterone only after 40 min. This indicates that aldosterone increases the uptake of RNA and protein precursors and the new synthesis of RNA and proteins. These events seem to to be regulated not continuously but intermittently. The induced proteins possibly take part in the mediation of the early hormone response. Experiments with the aldosterone antagonist, spironolactone, provide evidence for the specificity of the described hormone effects. The results after application of the Na+ channel blocker, amiloride, and the Na+/K(+)-ATPase inhibitor, G-strophanthin, indicate that the aldosterone effects are controlled by Na+ channels and Na+ pumps and therefore by the intracellular Na+ content. The inhibitory effect of cycloheximide on the aldosterone-induced protein synthesis indicates the role of these proteins on the hormone-stimulated Na+ transport.
...
PMID:Action of aldosterone on cultured renal collecting duct cells during the latent period. 170 11

The glycosylation of H+K(+)-ATPase vesicles isolated from hog gastric mucosa was investigated by various methods. Following protein separation on sodium dodecyl sulfate reducing gels and transfer to poly(vinyl difluoride) membranes, binding of concanavalin A was confined to the 94-kDa band which corresponds to the catalytic subunit. In contrast, wheat germ agglutinin binding occurred in a region below the 94-kDa subunit, corresponding to the 60-85-kDa region, and also to protein just above the catalytic subunit. Treatment with glycopeptidase F removed most of the concanavalin A staining and also the wheat germ agglutinin staining found below the 94-kDa region, but spared the higher molecular weight wheat germ agglutinin reactive material. During the deglycosylation experiments a protein of 35-kDa was produced. Sequencing analysis of V8 protease generated peptide fragments of the 35-kDa protein show at least 30% homology with the Na+K(+)-ATPase beta-subunits. Labeling of the carbohydrates by galactosyltransferase and [3H]uridine diphosphate-galactose showed that the sites of labeling were extracellular and were confined to the wheat germ agglutinin staining regions. Two molecular weight regions, below the 94-kDa region, of 60 and 85 kDa were identified. Electron microscopy using postembedding staining techniques showed that both concanavalin A and wheat germ agglutinin staining occurred on the extracellular face of the gastric vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Location of the carbohydrates present in the HK-ATPase vesicles isolated from hog gastric mucosa. 215 87

Adult Oryzias latipes were exposed to 50 mg of diethylnitrosamine per liter of water for 5 wk and then transferred to clean water for an additional 15 wk. Response of the liver during the first 6 wk were analyzed by enzyme histochemistry and by high-resolution light and transmission electron microscopy. After 1 wk, cytotoxicity was apparent at the light microscopic level by piecemeal necrosis and phagocytosis apoptosis by adjacent hepatocytes and resident macrophages. Spongiosis hepatis and inflammation, found as early as wk 3, were not widespread until wk 6. Glycogen depletion and multifocal increases in gamma-glutamyl transpeptidase were found as early as 3 wk. At 5 wk, macrophage infiltration and aggregation and hepatocyte lysosome proliferation were revealed by an increase in cells staining for acid phosphatase. In addition, a subpopulation of macrophages stained positively for glucose-6-phosphate dehydrogenase during wk 6. Other histochemical biomarkers (Mg2(+)-ATPase, DT-diaphorase, uridine diphosphoglucuronyl dehydrogenase) were not altered. Mitotic figures were rare for the entire 6-wk period. At the ultrastructural level, necrotic alterations of some hepatocytes were seen within 24 h. Within 48 h, an apparent reduction of hepatocyte glycogen and cell volume characterized the majority of hepatocytes; this was accompanied by an increase in interhepatocytic space and the length and complexity of the hepatocyte microvillous projections found in the space of Disse. Lipid vacuolar inclusions inhabited space previously occupied by glycogen. Margins of hepatocyte nuclei were irregular, and mitochondria were condensed and their shape altered so that crescentric and elongated profiles were abundant. Lysosomes and residual bodies were increased after 1 wk. The cytoplasmic processes delineating spongiotic lesions were identified as originating from Ito cells. After 4 wk, apparent proliferation of smooth endoplasmic reticulum and retention of transport lipid within its cisternae were seen. The toxic depletion of hepatocytes and the attendant altered cellular environment are discussed in relation to cell-to-cell interactions and the possible contribution of stromal and extracellular matrix changes to liver regeneration and neoplasia.
...
PMID:Cytotoxicity phase of diethylnitrosamine-induced hepatic neoplasia in medaka. 238 55

The avian salt gland provides an ideal system for the study of plasma membrane (PM) biogenesis. Feeding ducklings 1% sodium chloride (salt stress) induces the secretory cells of the gland to synthesize large amounts of PM, which forms an extensive basolateral PM domain after 7-9 days of treatment. In the present study, the initial biosynthetic events following salt stress were investigated. In vivo studies using 3H-uridine indicated that increased rates of RNA synthesis could be detected by 2 hr after the beginning of salt stress and continued through at least 12 hr. Under in vitro conditions, increased rates of protein and glycoprotein synthesis (as monitored by 3H-leucine and 3H-fucose incorporation, respectively) were also detected after 2 hr and continued through 7-9 days. Increased levels of Na,K-ATPase, a specific secretory cell PM marker, were detected after 8 hr of treatment as monitored by specific activity and 3H-ouabain binding. Sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis coupled with fluorography indicated that both 3H-leucine and 3H-fucose were incorporated into partially purified preparations of Na,K-ATPase isolated after 12 hr. Light microscopic autoradiographic analysis of pulse-chase experiments indicated that in secretory cells of 12-hr salt-stressed glands, 3H-leucine- and 3H-fucose-labelled products reached the cell periphery by 1-2 hr after the initial pulse. The incorporation of both tritiated precursors was predominantly associated with the secretory cells. Quantitative electron microscopic autoradiography indicated that 3H-leucine is initially taken up by elements of the rough endoplasmic reticulum (RER) and cytoplasm (5 min postpulse), subsequently transported to and concentrated within components of the Golgi apparatus (10 min of chase), and ultimately incorporated into all domains of the plasma membrane of secretory cells by 1-2 hr of chase. The data is consistent with a flow of newly synthesized membrane components from RER to Golgi to plasma membrane and is analogous to the pattern previously found for the synthesis and processing of PM proteins in a wide variety of cell types.
...
PMID:Plasma membrane biogenesis in the avian salt gland: a biochemical and quantitative electron microscopic autoradiographic study. 241 85

In this paper we examine the binding of Escherichia coli transcription termination factor rho to single-stranded RNA. Random polyribonucleotide copolymers containing low ratios of the fluorescent base 1,N6-ethenoadenosine have been synthesized using polynucleotide phosphorylase. Binding of rho to these polynucleotides elicits a significant increase in fluorescence, thus allowing either the direct monitoring of the titration of these polynucleotides with rho or measurement of the competitive displacement of the protein from these probes with other nucleic acids, even in the presence of biologically significant concentrations of ATP. By these techniques, it is shown that the binding site size (n) of rho protein to polynucleotides is 13(+/- 1) nucleotide residues per rho monomer (or 78(+/- 6) nucleotide residues per rho hexamer). Binding constants (K) and co-operativity parameters (omega) for the binding of rho to these polynucleotides have been measured as a function of nucleotide composition and of salt concentration. The results show that the affinity of rho for cytosine residues is quite strong and salt concentration independent, whilst binding to uridine residues is somewhat weaker and very salt concentration dependent. Poly(rC) and poly(dC) bind to rho competitively and with equal affinity and site size, although poly(rC) is the strongest cofactor for activating rho-dependent ATPase and poly(dC) has no ATPase cofactor activity at all. It is also shown that ATP (or ADP or ATP-gamma-S) binding does not change the binding site size of rho on RNA nor decrease its affinity for RNA binding. Circular dichroism measurements of rho binding to phage R17 RNA suggest that the affinity (K omega) of rho for RNA may be increased by ATP. The possible significance of these results for models of rho-dependent transcription termination is discussed in the companion paper.
...
PMID:Interactions of Escherichia coli transcription termination factor rho with RNA. I. Binding stoichiometries and free energies. 245 Oct 28

Two enzymatic activities that split diadenosine triphosphate have been reported in Escherichia coli: a specific Mg-dependent bis(5'-adenosyl) triphosphatase (EC 3.6.1.29) and the bis(5'-adenosyl) tetraphosphatase (EC 3.6.1.41). In addition to the activities of these two enzymes, a different enzyme activity that hydrolyzes dinucleoside polyphosphates is described. After purification and study of its molecular and kinetic properties, we concluded that it corresponded to the 5'-nucleotidase (EC 3.1.3.5) that has been described in E. coli. The enzyme was purified from sonic extracts and osmotic shock fluid. From sonic extracts, two isoforms were isolated by chromatography on ion-exchange Mono Q columns; they had a molecular mass of about 100 kilodaltons (kDa). From the osmotic shock fluid, a unique form of 52 kDa was recovered. Mild heating transformed the 100-kDa isoform to a 52-kDa form, with an increase in activity of about threefold. The existence of a 5'-nucleotidase inhibitor described previously, which associates with the enzyme and is not liberated in the osmotic shock fluid, may have been responsible for these results. The kinetic properties and substrate specificities of both forms (52 and 100 kDa) were almost identical. The enzyme, which is known to hydrolyze AMP and uridine-(5')-diphospho-(1)-alpha-D-glucose, but not adenosine-(5')-diphospho-(1)-alpha-D-glucose, was also able to split adenosine-(5')-diphospho-(5)-beta-D-ribose, ribose-5-phosphate, and dinucleoside polyphosphates [diadenosine 5',5'''-P1,P2-diphosphate,diadenosine 5',5'''-P1,P3-triphosphate, diadenosine 5',5'''-P1,P4-tetraphosphate, and bis(5'-guanosyl) triphosphate]. The effects of divalent cations and pH on the rate of the reaction with different substrates were studied.
...
PMID:Hydrolysis of bis(5'-nucleosidyl) polyphosphates by Escherichia coli 5'-nucleotidase. 255 71

Semen was collected under standardized conditions from men who were divided into three groups: a control group from normal spermiograms, men with abnormal spermiograms, and azoospermic men following vasectomy. Ultracentrifuged seminal plasma was analyzed for uridine, xanthine, urate, and the pelleted material for Mg2+- and Ca2+-dependent ATPase and protein. No significant intergroup differences were noted except the significant elevation of xanthine of vasectomized men. Uridine that occurs in high concentration in seminal plasma displayed a positive correlation to percentage motile sperms from the 26 men with normal and abnormal spermiograms. It was concluded that an optimal secretory function of uridine may parallel the increasing percentage of sperm with a better quality of motility. A linear relationship between ATPase activity and sperm penetration ability existed only when taken into consideration those 13 specimens with lowest enzyme activity.
...
PMID:Sperm motility and interactions among seminal uridine, xanthine, urate, and ATPase in fertile and infertile men. 293 76

Dolichyl phosphate concentrations, a primary factor in regulating the rate of N-glycosidically linked glycoprotein synthesis, are dependent upon a cytidine triphosphate (CTP)-dependent dolichol kinase. This study examines dolichol kinase in rat testicular microsomes and defines assay conditions. As with dolichol kinases from other tissues, addition of 2-mercaptoethanol increased activity 60%. Inclusion of NaF, an inhibitor of testicular dolichyl phosphate phosphatase activity, also resulted in a 38% increase in activity. Triton X-100 was necessary for phosphorylation of both endogenous and exogenous dolichol; however, concentrations of detergent in excess of 0.25-0.35% were inhibitory. A 2- to 5-fold stimulation of kinase activity was obtained by addition of 50-100 microM exogenous dolichol. The high level of nucleoside triphosphatase activity in testicular microsomes mandated the inclusion of high levels of uridine triphosphate (UTP) to protect the [gamma-32 P] CTP. Increasing UTP concentrations up to 50 mM resulted in increased product formation. A clear requirement for divalent cations was observed; 5 mM ethylenediaminetetraacetate (EDTA) abolished activity. The following order of cation effectiveness was observed: Mn greater than or equal to Ca greater than Cd greater than Zn much greater than Mg. Ten mM optima were established for Ca2+ and Mn2+; the presence of UTP, however, results in significantly reduced concentrations of free Ca2+. Ion combination studies demonstrated interactive inhibitory effects between Ca2+ and other stimulatory divalent cations. Addition of 2 microM brain calmodulin, in the presence of 10 mM Ca2+, resulted in a 75-100% stimulation of activity.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Dolichol kinase activity in the developing rat testis. 300 68

The phospholipid polar head group composition of LM cell plasma membranes was nutritionally altered by choline analogue supplementation. Phosphatidylcholine (PC), normally 60% of total phospholipid, was depleted by 60 to 90% in membranes from cells cultured with N, N'-dimethylethanolamine (DME), N-monomethylethanolamine (ME), and ethanolamine (E). Enrichment of LM cell membranes with choline analogues, such as DME-, ME-, and E-containing phospholipids, decreased the transport of [3H]thymidine, [3H]2-deoxy-D-glucose, and [14C]3-O-methylglucose. Conversely, no change in the transport of [3H] uridine or [14C]aminoisobutyric acid was observed. The toxicity of antineoplastic drugs such as 5-fluorouracil, but not daunorubicin, doxorubicin, or methotrexate, was enhanced threefold in cells enriched with phospholipid containing choline or DME as compared to ME or E. Arrhenius plots of Na+-K+-ATPase activity demonstrated a characteristic temperature at 29 degrees C in plasma membranes from choline-fed cells, while those from analogue-fed cells showed an additional break at 20 degrees C and had higher energies of activation below this temperature. In addition, choline analogue supplementation altered the protein composition of the plasma membrane. The results reported herein demonstrate that nutritional alteration of LM fibroblast plasma membrane phospholipid polar head group composition affects several transport processes and toxicity of some anticancer drugs.
...
PMID:Membrane phospholipids alter nutrient transport and drug toxicity in tumorigenic fibroblasts. 303 53

Mammalian cells treated with low concentrations of phospholipase C become permeable to the protein toxin alpha-sarcin. A similar permeabilization is not induced upon treatment with other lipases such as phospholipase A2, sphingomyelinase, or cholesterol esterase. Concentrations of 10 micrograms/ml alpha-sarcin almost completely blocked translation in HeLa cells treated with 0.3 U/ml phospholipase C (PL-C) for 1 h. In contrast, 200 micrograms/ml of alpha-sarcin had no effect at all on protein synthesis in untreated cells. Other macromolecules such as horseradish peroxidase and luciferase also enter into cells if they are treated with phospholipase C. This permeabilization method is fully reversible. As soon as 5 min after PL-C removal, the cells become impermeable to alpha-sarcin. Other metabolites such as uridine nucleotides are partially released after PL-C incubation, whereas the content of 86Rb+ remains at control levels, probably because the Na+/K+ ATPase activity increases.
...
PMID:Exogenous phospholipase C permeabilizes mammalian cells to proteins. 313 47


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---