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)

Adenosine triphosphatase (ATPase) activity and acid phosphatase activity in lymphocytes from patients with carcinoma of the gastrointestinal tract were determined in order to investigate whether or not changes in these enzyme activities has any relation to the immune reactivity of carcinoma-bearing patients. In patients with a performance status of more than 60%, the mean value of the total ATPase activity in lymphocytes differed little from that in controls, but the mean value of the oligomycin-sensitive ATPase activity decreased as compared to that in the controls. On the other hand, the mean values of the activities of both free and total acid phosphatase in lymphocytes increased as compared to those in controls. The mean values of the activities of both ATPase and acid phosphatase in lymphocytes from patients whose performance status was less than 50% decreased as compared to those from controls and patients whose performance status was more than 60%. The change of the activities of both ATPase and acid phosphatase in lymphocytes has relation to that of the immunological parameters of the patients with carcinoma of the gastrointestinal tract. These results indicate that both ATPase and acid phosphatase in lymphocytes may play an important role in the immune mechanism.
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PMID:Changes of enzyme activities recognized in lymphocytes from patients with carcinoma of the gastrointestinal tract. 622 54

The soluble form of mitochondrial adenosine triphosphatase was purified in an electrophoretically and immunologically pure form from sweet potato root tissue. The enzyme consisted of six kinds of subunits with different molecular weights (52,500, 51,500, 35,500, 26,000, 23,000, and 12,000), and its molecular weight was about 370,000. Adenosine triphosphatase associated with the submitochondrial particles was oligomycin-sensitive and heat-labile, whereas the soluble form of the enzyme was oligomycin-insensitive and cold-labile. The enzyme in either the membrane-bound or the soluble form showed negative cooperativity. Both experiments with polyacrylamide gel electrophoresis and immunological methods suggest that some of the subunits, probably those with molecular weights of 52,500 and 51,500, are dissociated from the enzyme protein during storage of the enzyme preparations.
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PMID:Purification and characterization of the soluble form of mitochondrial adenosine triphosphatase from sweet potato. 622 90

In vitro movement of fibrils composed of actin and myosin filaments purified from skeletal muscle was observed by dark field microscopy during superprecipitation at low ionic strengths at room temperature. The movement was activated by phosphorylation of light chain (LC2) of myosin. The activity of the movement was evaluated in terms of the spreading of the area where the fibrils were moving. Adenosine triphosphatase activity of actomyosin was also enhanced by phosphorylation of LC2 and was correlated with the activity of the in vitro movement.
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PMID:Phosphorylation of myosin light chain modulates the in vitro movement of fibrils composed of actin and myosin filaments from skeletal muscle. 622 49

Adenosine triphosphatase activity which is Mg2+-dependent and stimulated by submicromolar concentrations of Ca2+ (as Ca . ATP) was identified in the total particulate fraction of rat pancreatic acini. Half-maximal activity (V0.5) is obtained at 100.1 +/- 6 nM Ca . ATP with a Hill coefficient of 2.2 +/- 0.1 (mean +/- S.E.; n = 4). Maximal activity was 75 +/- 19 pmol of Pi released from ATP minute-1 microgram of membrane protein-1 (mean +/- S.E.; n = 7). High affinity Ca2+-ATPase activity was unaffected by ouabain, Na+, K+, La3+, and added calmodulin. Activity was slightly reduced by ruthenium red (0.1 mM) and by oligomycin (80 micrograms/ml) but was reduced almost 50% by the phenothiazine derivative fluphenazine in a dose-related and Ca2+-dependent manner. Hydrolysis of p-nitrophenyl phosphate was 9% of the rate of ATP hydrolysis and was independent of Ca2+ concentration. However, ADP, GTP, UTP, and ITP were hydrolyzed at 76-93% the rate that ATP was hydrolyzed with V0.5 values and Hill coefficients similar to those of Ca . ATP. We conclude that rat pancreatic acini contain an enzyme for active Ca2+ translocation: ATPase activity that is Mg2+-dependent and stimulated by submicromolar concentrations of Ca . ATP. Substrate hydrolysis appears to involve positive cooperative interactions of multiple ligand-binding sites and may be regulated in part by calmodulin.
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PMID:High affinity, calcium-stimulated adenosine triphosphatase activity in the particulate fraction of rat pancreatic acini. 623 78

Reduced glutathione (0.3 mM) stimulates the activity of sodium-potassium activated ATPase (Na+K+ATPase) by 54% in plasma membranes prepared from bovine corneal endothelial cells. Oxidized glutathione, however, has no effect on Na+K+ATPase activity in the same tissue, although it does inhibit magnesium activated ATPase (Mg++ATPase) by approximately 30%. Adenosine neither stimulates nor inhibits either Na+K+ATPase or Mg++ATPase in these plasma membranes. It is postulated that the stimulatory effect of glutathione on deturgescence stems from the direct reaction of the reduced form of the tripeptide on sulfhydryl groups located on plasma membranes of corneal endothelial cells. It is highly probable that these sulfhydryl groups are part of the Na+k+ATPase complex itself.
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PMID:The effects of glutathione and adenosine on plasma membrane ATPases of the corneal endothelium. An hypothesis on the stimulatory mechanism of perfused glutathione upon deturgescence. 627 70

Cells of the intercalary ducts showed concentrations of secretory granules adjacent to the luminal plasma membrane. Evidence of thiamine-pyrophosphatase activity was seen in the Golgi apparatus and of acid-phosphatase activity in GERL-like structure, lysosomes and immature secretory granules. Adenosine-triphosphatase reaction-product was present along surfaces of myoepithelial cells and to a lesser extent along contiguous surfaces of duct cells. The findings indicate secretory activity in the intercalary duct cells.
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PMID:Ultrastructural phosphatase cytochemistry of the intercalary ducts of the parotid and submandibular salivary glands of man. 628 Jun 55

Adenosine triphosphatase activity of U. urealyticum is an integral membrane-bound protein which cannot be detached from the membrane by mild treatment with EDTA in low-ionic strength media nor by ionic detergents which rapidly inactivated the enzyme. The enzyme was Mg++ dependent; Mn++ and Co++ could replace Mg++ to some extent. A slight stimulatory effect was also exerted by sodium and lithium. The enzyme showed a nucleotide triphosphatase activity, but ADP was hydrolyzed at close to 40% the rate of ATP and other nucleotide monophosphatase were hydrolyzed at a very slow rate. Oubain and oligomycin did not inhibit the adenosine triphosphatase activity, whereas DCCD, NBD-Cl and several sulfhydryl-blocking reagents strongly reduced its activity. The enzyme could not be stimulated by trypsin pretreatment. It seems that the complex enzyme is tightly linked to the lipid bilayer of the membrane and differs in many aspects from the F0-F1 (Mg++, Ca++)-ATPase of bacteria.
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PMID:Adenosine triphosphatase activity of Ureaplasma urealyticum. 628 75

Adenosine has been reported by several investigators to stimulate corneal deturgescence, but the actual biochemical mechanism of this effect remains unknown. Effects observed include increased magnitude and rate of corneal thinning, increased endothelial fluid transport rate, support of adenosine triphosphate (ATP) levels, stimulation of magnesium activated ATPase (Mg++ATPase) and sodium-potassium activated ATPase (Na+K+ ATPase) activities in endothelium whole cell preparations, but a lack of stimulation of Mg++ATPase and Na+K+ATPase activities in endothelial plasma membrane preparations. This study examined the possibility that adenosine alters the corneal endothelial levels of two biochemical effectors: adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP). Bovine corneal endothelium was studied as fresh tissue and after growth in tissue culture. The samples were processed both at room temperature and in liquid nitrogen. Incubation of fresh and cultured endothelia in media containing adenosine was found to have no effect on the cAMP and cGMP levels regardless of the processing method. The data suggest that cyclic nucleotides do not mediate adenosine-stimulated corneal deturgescence.
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PMID:Null effect of adenosine on cyclic nucleotides of the corneal endothelium: possible implications for adenosine-stimulated corneal deturgescence. 632 99

Crystalline complexes of tyrosyl-tRNA synthetase from Bacillus stearothermophilus were prepared with adenosine, AMP, ATP and PPi, all in the presence of tyrosinol, which binds strongly to the tyrosine binding site but cannot be adenylated by ATP. The hydrolysis of ATP in the presence of crystalline tyrosyl-tRNA synthetase (or redissolved crystals) was checked in the absence of tyrosine or with tyrosinol. No ATPase activity due to the enzyme was detected under these conditions. Difference Fourier analysis shows that tyrosinol binds to the tyrosine binding site with the same occupancy as the amino acid. Comparison between tyrosine and tyrosinol shows the location of the extra oxygen atom of the tyrosine carboxylate. Adenosine, AMP and ATP are weakly bound to the enzyme in the presence of tyrosinol. Even when ATP is present at a concentration greater than Km for adenylation, it is not sufficiently strongly bound to give a recognizable density for adenine. However, some significant peaks of density are present near the tyrosine binding site. One of them is at the usual ribose binding site, and may possibly represent ribose binding with a low occupancy. When AMP is bound a similar but not identical arrangement of density is observed.
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PMID:Interaction of crystalline tyrosyl-tRNA synthetase with adenosine, adenosine monophosphate, adenosine triphosphate and pyrophosphate in the presence of tyrosinol. 632 20

The development of colonic water and electrolyte transport was studied in rats. The colon of 20-day-old (young) and 40-day-old (adult) rats was perfused with either a hypotonic (200 mosmol/L) or a hypertonic (450 mosmol/L) solution. The solutions had identical electrolyte contents. Polyethylene glycol was used as a marker of water absorption. Na,K-Adenosine triphosphatase (Na,K-ATPase) activity was determined in nonperfused colonic segments in 10- to 40-day-old rats. Water absorption was always higher in young rats than in adult rats. In the young rats but not in the adult rats increased osmotic pressure of the luminal fluid resulted in a significant decrease in water absorption. The secretion of K was observed only in adult rats. Na,K-ATPase activity increased significantly from 10 to 20 and from 20 to 40 days of age. The results imply that the immature colon has higher water conductivity and low active electrolyte transport.
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PMID:Colonic water and electrolyte transport in young and adult rats. 633 Mar 39


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