scholarly journals Differential effects of temperature on a membrane adenosine triphosphatase and associated phosphatase

1975 ◽  
Vol 151 (2) ◽  
pp. 439-442 ◽  
Author(s):  
J A Walker ◽  
K P Wheeler
Keyword(s):  
Atpase Activity ◽  
Phosphatase Activity ◽  
Adenosine Triphosphatase ◽  
Arrhenius Plots ◽  
Differential Effects ◽  
Adenosine Triphosphatase Activity ◽  
Dependent Atpase ◽  
Effects Of Temperature

Arrhenius plots of a membrane (Na+ + K+)-dependent ATPase (adenosine triphosphatase) activity showed characteristic discontinuities, whereas those of the associated K+-dependent phosphatase activity did not. These findings support the contention that the phosphatase activity does not depend on phospholipid in the same way as does the ATPase activity.

scholarly journals No major thermogenic role for (Na+ + K+)-dependent adenosine triphosphatase apparent in hepatocytes from hyperthyroid rats

1982 ◽  
Vol 202 (3) ◽  
pp. 661-665 ◽  
Author(s):  
D G Clark ◽  
M Brinkman ◽  
O H Filsell ◽  
S J Lewis ◽  
M N Berry
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Atpase Activity ◽  
Heat Production ◽  
Adenosine Triphosphatase ◽  
Heat Output ◽  
Liver Parenchymal ◽  
Dependent Atpase ◽  
Parenchymal Cells ◽  
Isolated Liver

(Na+ + K+)-dependent ATPase activity, heat production and oxygen consumption were increased by 59%, 62% and 75% respectively in hepatocytes from tri-iodothyronine-treated rats. Ouabain at concentrations of 1 and 10 mM decreased oxygen uptake by 2-8% in hepatocytes from euthyroid rats and by 5-15% in hepatocytes from hyperthyroid animals. Heat output was decreased by 4-9% with the glycoside in isolated liver parenchymal cells from the control animals and by 11% in the cells from the tri-iodothyronine-treated animals. These results do not support the hypothesis that hepatic (Na+ + K+)-ATPase plays a major role in increased heat production in hepatocytes from hyperthyroid rats.

scholarly journals Partial diploids of Escherichia coli carrying normal and mutant alleles affecting oxidative phosphorylation

1977 ◽  
Vol 162 (3) ◽  
pp. 665-670 ◽  
Author(s):  
F Gibson ◽  
G B Cox ◽  
J A Downie ◽  
J Radik
Keyword(s):  
Escherichia Coli ◽  
Fluorescence Quenching ◽  
Oxidative Phosphorylation ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Growth Yields ◽  
Normal Allele ◽  
Adenosine Triphosphatase Activity

A plasmid was isolated which included the region of the Escherichia coli chromosome carrying the known genes concerned with oxidative phosphorylation (unc genes). This plasmid was used to prepare partial diploids carrying normal unc alleles on the episome and one of the three mutant alleles (unc A401, uncB402 or unc-405) on the chromosome. These strains were compared with segregants from which the plasmid had been lost. Dominance of either normal ormutant unc alleles was determined by growth on succinate, growth yields on glucose, Mg-ATPase (Mg2+-stimulated adenosine triphosphatase) activity, atebrin-fluorescence quenching, ATP-dependent transhydrogenase activity and oxidative phosphorylation. In all the above tests, dominance of the normal allele was observed. However, in membranes from the diploid strains which carried a normal allele and either of the mutant alleles affecting Mg-ATPase activity (uncA401 or unc-405), the energy-linked functions were only partially restored.

scholarly journals Role of phospholipid in the intermediate steps of the sodium-plus-potassium ion-dependent adenosine triphosphatase reaction

1975 ◽  
Vol 146 (3) ◽  
pp. 729-738 ◽  
Author(s):  
K P Wheeler
Keyword(s):  
Phosphatase Activity ◽  
Adenosine Triphosphatase ◽  
Atp Hydrolysis ◽  
Reaction Sequence ◽  
Single Extraction ◽  
Background Value ◽  
Dependent Atpase ◽  
Membrane Atpase ◽  
Normal Enzyme

The phosphorylation and dephosphorylation steps of the (Na-++K-+)-dependent ATPase (adenosine triphosphatase) (EC 3.6.1.3) reaction have been compared in ‘normal’, lipid-depleted and ‘restored’ membrane ATPase preparations. Partial lipid depletion was achieved by a single extraction with Lubrol W, and ‘restoration’ by adding pure phosphatidylserine. γ-32-P-labelled ATP was used for phosphorylation. The main findings were as follows. (1) Partial lipid depletion decreased but did not prevent Na-+-dependent phosphorylation, although it virtually abolished both Na-+-dependent and (Na-++K-+)-dependent ATPase activities. (2) ‘Restoration’ with phosphatidylserine produced an increment in phosphorylation that was the same in the presence and absence of added Na-+. (3) K-+ decreased the extent of Na-+-dependent phosphorylation of the depleted enzyme without producing a corresponding release of Pi. (4) K-+ rapidly decreased the extent of phosphorylation of the ‘restored’ enzyme to near-background value, with a concomitant release of Pi. (5) Na-+-dependent ATP hydrolysis was not restored. (6) The turnover of the ‘restored’ enzyme seemed to be higher than that of the ‘normal’ enzyme. The reaction sequence is discussed in relation to these results and the fact that the depleted enzyme retained about 50% of K-+-dependent phosphatase activity.

Effect of Electroconvulsive Therapy on Erythrocyte Adenosine Triphosphatase Activity in Depressive Illness

1980 ◽  
Vol 137 (4) ◽  
pp. 343-345 ◽  
Author(s):  
L. J. Whalley ◽  
M. Scott ◽  
H. W. Reading ◽  
J. E. Christie
Keyword(s):  
Atpase Activity ◽  
Erythrocyte Membrane ◽  
Electroconvulsive Therapy ◽  
Healthy Subjects ◽  
Adenosine Triphosphatase ◽  
Depressive Illness ◽  
Slight Reduction ◽  
Acute Effects ◽  
Adenosine Triphosphatase Activity ◽  
Depressed Patients

SummaryErythrocyte membrane adenosine triphosphatase activities were examined in twelve unipolar depressed patients receiving ECT. Eleven patients undergoing diagnostic cystoscopy served as controls for the acute effects of anaesthesia, and sixteen healthy subjects served as non-depressed controls. The unipolar depressed patients had a slight reduction in their (Na++K+)-ATPase activity but effective ECT treatment was not associated with any increase in this activity. This approach is unlikely to cast further light on the membrane phenomenology of depressive illness.

scholarly journals Involvement of the endogenous inhibitor protein in the MgATP-induced inhibition of soluble mitochondrial adenosine triphosphatase activity

1981 ◽  
Vol 200 (3) ◽  
pp. 655-661 ◽  
Author(s):  
P N Lowe ◽  
R B Beechey
Keyword(s):  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Heart Mitochondria ◽  
Inhibitor Protein ◽  
Endogenous Inhibitor ◽  
Adenosine Triphosphatase Activity

Chloroform-released ATPase from ox heart mitochondria contains significant amounts of inhibitor protein. There is a correlation between processes that affect the interactions between the inhibitor protein and the ATPase molecule and the ability of MgATP to induce an inhibition of ATPase activity. Evidence is presented suggesting that the endogenous inhibitor protein is involved in the process of MgATP-induced inhibition of soluble ATPase activity.

The histochemical demonstration of myofibrillar adenosine triphosphatase activity in fish muscle

1974 ◽  
Vol 52 (7) ◽  
pp. 871-877 ◽  
Author(s):  
I. A. Johnston ◽  
S. Patterson ◽  
P. Ward ◽  
G. Goldspink
Keyword(s):  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Fish Muscle ◽  
Histochemical Demonstration ◽  
Differential Staining ◽  
Fiber Types ◽  
Myofibrillar Atpase ◽  
Adenosine Triphosphatase Activity ◽  
Acid Ph ◽  
Myofibrillar Atpase Activity

A technique for the demonstration of myofibrillar adenosine triphosphatase activity (ATPase) used for mammalian muscle has been modified to suit fish muscle. The mammalian method involves selectively inhibiting fiber types by preincubation at either alkaline (pH 10.4) or acid (pH 4.3) pH before incubation for myofibrillar (ATPase) activity. Fish muscle fibers were found to be generally inactivated under these conditions. Preincubation at an acid pH was found to be unsuitable for fish muscle because of the indiscriminate inactivation of the fibers. The effects of preincubating at pH 10.4 and incubating tissue sections for different time periods and at different pH's and temperatures have been investigated. A differential staining of fiber types correlated with biochemical data on myofibrillar ATPase for red and white muscles was obtained by preincubating sections for short periods (1–2 min) at pH 10.4. Under these conditions the intermediately positioned pink fibers were found to stain similarly to the white fibers of high myofibrillar ATPase activity. An investigation has been made of the qualitative distribution of fiber types in the myotomal muscle of live teleost species: coalfish (Gadus virens), grey mullet (Mugil cephalus), crucian carp (Carassius carassius), black mollie (Mollienesia sp), and glassfish (Chanda ranga). The pink fibers were found to be abundant in all the species examined with the exception of the glassfish.

scholarly journals ADENOSINE TRIPHOSPHATASE: A NEUROHISTOCHEMICAL STUDY

1962 ◽  
Vol 10 (6) ◽  
pp. 731-740 ◽  
Author(s):  
D. NAIDOO
Keyword(s):  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Wistar Rat ◽  
The Other ◽  
Nuclear Staining ◽  
Adenosine Triphosphatase Activity ◽  
Bivalent Cations ◽  
Vascular Elements ◽  
The Brain ◽  
Cerebral Vascular

The location of adenosine triphosphatase in the brain has been studied in rapidly frozen-dried cerebral tissues of the Wistar rat. It is found that adenosine triphosphatase is an almost exclusively nuclear enzyme. Two tissue fractions of the cerebrum were separated, so that one sample was made up of vascular elements, and the other of neural elements. The two fractions were then studied for their adenosine triphosphatase activity, and compared with the histochemical findings. The two tissue fractions were found not to differ in the absence of bivalent cations. When Ca++ were added to the cerebral vascular suspension, ATPase activity was increased approximately 15 times, and only 3 times in the presence of Mg++. Conversely, the addition of Mg++ increased the ATPase activity of the neural fraction 200%; whereas, Ca++ was responsible for a 60% increase. This fact was detectable microscopically when Ca++ was found to intensify vascular nuclear staining, and Mg++ to increase the neuronal and glial nuclear staining. The results, histochemical and biochemical, are mutually confirmatory.

scholarly journals A simple and rapid method for the reversible removal of lipids from a membrane-bound enzyme

1978 ◽  
Vol 169 (2) ◽  
pp. 305-311 ◽  
Author(s):  
S L Goodman ◽  
M Isern de Caldentey ◽  
K P Wheeler
Keyword(s):  
Phosphatase Activity ◽  
Rapid Method ◽  
Adenosine Triphosphatase ◽  
Complete Loss ◽  
Initial Activity ◽  
Experimental Conditions ◽  
Adenosine Triphosphatase Activity ◽  
Ionic Detergent ◽  
Reproducible Method ◽  
Membrane Bound

A simple, rapid and reproducible method for the reversible removal of lipids from a membrane-bound enzyme is described. Essentially, a membrane preparation containing (Na+ + K+)-dependent adenosine triphosphatase was extracted with the non-ionic detergent Lubrol WX in the presence of glycerol, and partial separation of protein from lipid was achieved with the use of only two centrifugations. About 74% of the endogenous phospholipid and 79% of the cholesterol were removed, concomitant with a virtually complete loss of ouabain-sensitive adenosine triphosphatase activity, but with retention of 60-100% of the K+-dependent phosphatase activity. The addition of pure phosphatidylserine re-activated the enzyme to more than 80% of the initial activity, and up to 30% of the protein was recovered. Excess of phosphatidylserine could be washed off the enzyme to give a stable ‘reconstituted’ preparation. The effects of variation in the experimental conditions were examined, and the results are discussed with respect to the possibility of adapting the method to the study of other lipid-dependent enzymes bound to membranes.

scholarly journals Calcium ion-dependent p-nitrophenyl phosphate phosphatase activity and calcium ion-dependent adenosine triphosphatase activity from human erythrocyte membranes

1973 ◽  
Vol 136 (1) ◽  
pp. 185-194 ◽  
Author(s):  
Alcides F. Rega ◽  
Donaldo E. Richards ◽  
Patricio J. Garrahan
Keyword(s):  
Cell Membrane ◽  
Phosphatase Activity ◽  
Human Erythrocyte ◽  
Calcium Ion ◽  
Adenosine Triphosphatase ◽  
Erythrocyte Membranes ◽  
Dependent Atpase ◽  
Nitrophenyl Phosphate ◽  
Inner Surface ◽  
Human Erythrocyte Membranes

In the presence of ATP and of Mg2+, human erythrocyte membranes show a phosphatase activity towards p-nitrophenyl phosphate which is activated by low concentrations of Ca2+. The effect of Ca2+ is strongly enhanced if either K+ or Na+ is also present. Activation of the p-nitrophenyl phosphate phosphatase by Ca2+ reaches a half-maximum at about 8μm-Ca2+ and is apparent only when the ion has access to the inner surface of the cell membrane. Ca2+-dependent phosphatase activity can only be observed if ATP is at the inner surface of the cell membrane, and the presence of ATP seems to be absolutely necessary, since either its removal or its replacement by other nucleoside triphosphates abolishes the activating effect of Ca2+. The properties of the (ATP+Ca2+)-dependent phosphatase are very similar to those of the Ca2+-dependent ATPase (adenosine triphosphatase), also present in erythrocyte membranes, which probably is involved in Ca2+ transport in erythrocytes. The similarities suggest that both activities may be properties of the same molecular system. This view is further supported by the fact that p-nitrophenyl phosphate inhibits to a similar extent Ca2+-dependent ATPase activity and ATP-dependent Ca2+ extrusion from erythrocytes.

Localization of adenosine triphosphatase activity in motile bacteria

1973 ◽  
Vol 19 (10) ◽  
pp. 1265-1267 ◽  
Author(s):  
Z. Vaituzis
Keyword(s):  
Escherichia Coli ◽  
Atpase Activity ◽  
Uniform Distribution ◽  
Adenosine Triphosphatase ◽  
Periplasmic Space ◽  
Reaction Products ◽  
Adenosine Triphosphatase Activity ◽  
Atpase Reaction ◽  
Motile Bacteria

Cytochemical studies on motile bacteria revealed magnesium-dependent adenosine triphosphatase (ATPase) activity at the membranous sites of flagellar origin. The studies were done on bacteria representing three types of flagellation, namely, peritrichate, lophotrichate, and monotrichate. Escherichia coli and S. serpens showed a uniform distribution of ATPase reaction products throughout the periplasmic space. In B. licheniformis and V. metchnikovii the reaction products were found in the cytoplasm accumulated in areas where flagella originate.

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