scholarly journals Comparison of some minor activities accompanying a preparation of sodium-plus-potassium ion-stimulated adenosine triphosphatase from pig brain

1968 ◽  
Vol 106 (1) ◽  
pp. 113-121 ◽  
Author(s):  
M. Fujita ◽  
K. Nagano ◽  
N. Mizuno ◽  
Y. Tashima ◽  
T. Nakao ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Atpase Activity ◽  
Ultrasonic Treatment ◽  
Adenosine Triphosphatase ◽  
Enzyme Preparation ◽  
Sodium Iodide ◽  
Low Ph ◽  
Pig Brain ◽  
Brain Microsomes ◽  
Decreasing Ph

1. An ATPase (adenosine triphosphatase) preparation obtained from pig brain microsomes by treatment with sodium iodide showed four apparently different ouabain-sensitive activities under various conditions. They were (a) ouabain-sensitive Mg2+-stimulated ATPase, (b) K+-stimulated ATPase, (c) (Na+,K+)-stimulated ATPase and (d) Na+-stimulated ATPase activities. 2. These activities showed the same substrate specificity, ATP being preferentially hydrolysed and CTP slightly. AMP was not hydrolysed. 3. These activities were inhibited by low concentration of ouabain. The concentration producing 50% inhibition was 0·1μm for ouabain-sensitive Mg2+-stimulated ATPase, 0·2μm for K+-stimulated ATPase, 0·1μm for (Na+,K+)-stimulated ATPase and 0·003μm for Na+-stimulated ATPase activity. 4. The ouabain-sensitive ATPase activities were inactivated by N-ethylmaleimide but the insensitive ATPase activity was not. 5. The three ouabain-sensitive ATPase activities were inhibited about 50% by 1mm-Ca2+, whereas the ouabain-sensitive Mg2+-stimulated ATPase activity was activated by the same concentration of Ca2+. The preparation was treated with ultrasonics at 20kcyc./sec. The 2min. ultrasonic treatment inactivated the ATPase activities by 50%. 7. The temperature coefficient Q10 was 6·6 for K+-stimulated ATPase activity, 3·7 for (Na+,K+)-stimulated ATPase and 2·6 for Na+-stimulated ATPase. 8. Organic solvents inactivated the ATPase activities, to which treatment the K+-stimulated ATPase was the most resistant. 9. The phosphorylation of the enzyme preparation became less dependent on Na+ with decreasing pH. This Na+-independent phosphorylation at low pH was sensitive to K+ and hydroxylamine as well as the Na+-dependent phosphorylation at neutral pH.

scholarly journals The sodium-plus-potassium ion-activated adenosine triphosphatase of cerebral microsomal fractions: treatment with disrupting agents

1967 ◽  
Vol 102 (3) ◽  
pp. 675-683 ◽  
Author(s):  
J. R. Cooper ◽  
H. Mcilwain
Keyword(s):  
Atpase Activity ◽  
Protective Effect ◽  
Ammonium Sulphate ◽  
Ultrasonic Treatment ◽  
Adenosine Triphosphatase ◽  
Microsomal Fraction ◽  
Centrifugal Forces ◽  
Microsomal Preparation ◽  
Fold Enrichment ◽  
Low Concentrations

1. The Na(+)-plus-K(+)-stimulated adenosine triphosphatase [(Na(+),K(+))-ATPase] of microsomal preparations from ox brain was inactivated or diminished in activity by exposure to 2-8m-urea. Similar concentrations of urea diminished the turbidity of the suspensions. 2. Low concentrations (about 2.5mm) of NaATP with the urea gave partial or complete protection of the ATPase, without altering the concomitant change in turbidity. Some protection of the (Na(+),K(+))-ATPase was afforded by tris ATP, but the greatest protection was found with NaATP and in its presence the change in (Na(+),K(+))-ATPase with 3m-urea included a phase in which activity was enhanced by 40%. 3. The protective effect was specific to NaATP: KATP, NaADP, NaAMP and sodium pyrophosphate were without protective effect and in some cases they augmented the action of urea. 4. The turbidity of cerebral microsomal suspensions was diminished also by ultrasonic irradiation; NaATP did not alter this change. After ultrasonic treatment up to 55% of the protein and of the ATPase activity were no longer deposited by centrifugal forces of 4.5x10(6)g-min. 5. Ultrasonic treatment and centrifugation could be carried out with little or no loss of ATPase and ammonium sulphate flocculation of the supernatant then afforded in the first material precipitated a three- to five-fold enrichment of (Na(+),K(+))-ATPase activity. 6. Sodium borohydride and dimethyl sulphoxide also diminished the turbidity of the microsomal fraction but enrichment of the ATPase was not effected by these reagents; ten other compounds were without action on the ATPase. 7. Acetyl phosphate was hydrolysed by the microsomal preparation and this activity was increased by added K(+). Acetyl-phosphatase activity persisted in the ultrasonically treated and ammonium sulphate-fractionated preparations, which were more exacting in their requirements for K(+). 8. The findings are discussed in relation to the mechanism of the (Na(+),K(+))-ATPase.

Localization of Adenosine Triphosphatase Activity in the Phleom of Nicotiana Tabacum

1972 ◽  
Vol 30 ◽  
pp. 230-231
Author(s):  
James Cronshaw ◽  
Jamison E. Gilder
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Higher Plants ◽  
High Surface ◽  
Root Tip ◽  
Animal Cells ◽  
Physiological Processes ◽  
Tip Cells ◽  
Atpase Localization

Adenosine triphosphatase (ATPase) activity has been shown to be associated with numerous physiological processes in both plants and animal cells. Biochemical studies have shown that in higher plants ATPase activity is high in cell wall preparations and is associated with the plasma membrane, nuclei, mitochondria, chloroplasts and lysosomes. However, there have been only a few ATPase localization studies of higher plants at the electron microscope level. Poux (1967) demonstrated ATPase activity associated with most cellular organelles in the protoderm cells of Cucumis roots. Hall (1971) has demonstrated ATPase activity in root tip cells of Zea mays. There was high surface activity largely associated with the plasma membrane and plasmodesmata. ATPase activity was also demonstrated in mitochondria, dictyosomes, endoplasmic reticulum and plastids.

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.

Effect of high salt intake on sodium, potassium-dependent adenosine triphosphatase activity in the erythrocytes of normotensive men

1988 ◽  
Vol 75 (2) ◽  
pp. 167-170 ◽  
Author(s):  
Antonio P. Quintanilla ◽  
Maria I. Weffer ◽  
Haengil Koh ◽  
Mohammed Rahman ◽  
Agostino Molteni ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Inorganic Phosphate ◽  
Adenosine Triphosphatase ◽  
Salt Intake ◽  
Control Period ◽  
Plasma Renin ◽  
Normal Diet ◽  
High Salt ◽  
Sodium Potassium ◽  
High Salt Intake

1. We measured ouabain-insensitive adenosine triphosphatase (ATPase), sodium, potassium-dependent adenosine triphosphatase (Na+,K+-ATPase) and intracellular Na+ and K+ in the erythrocytes of 19 healthy volunteers, before and after supplementation of their normal diet with 6.0–8.9 g of salt (102–137 mmol of NaCl) per day, for 5 days. 2. The subjects had a small but significant gain in weight. Mean plasma renin activity decreased from 1.57 to 0.73 pmol of angiotensin I h−1 ml−1 and plasma aldosterone from 0.46 to 0.24 nmol/l. 3. Total ATPase activity fell from 197.9 nmol of inorganic phosphate h−1 mg−1 during the control period to 173.5 during the high-salt period (P < 0.0125). Na+,K+-ATPase activity fell from 162.2 to 141.4 nmol of inorganic phosphate h−1 mg−1 (P < 0.05). Intracellular Na + and intracellular K+ did not change. 4. These results are consistent with the hypothesis that salt-induced volume expansion causes the release of a factor inhibitory to the Na+ pump.

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.

DNA loop extrusion by human cohesin

Science ◽  
2019 ◽  
Vol 366 (6471) ◽  
pp. 1338-1345 ◽  
Author(s):  
Iain F. Davidson ◽  
Benedikt Bauer ◽  
Daniela Goetz ◽  
Wen Tang ◽  
Gordana Wutz ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Atpase Activity ◽  
Chromatin Structure ◽  
Adenosine Triphosphatase ◽  
Gene Recombination ◽  
Loop Formation ◽  
Base Pairs ◽  
Topologically Associating Domains ◽  
Dna Loop ◽  
Eukaryotic Genomes

Eukaryotic genomes are folded into loops and topologically associating domains, which contribute to chromatin structure, gene regulation, and gene recombination. These structures depend on cohesin, a ring-shaped DNA-entrapping adenosine triphosphatase (ATPase) complex that has been proposed to form loops by extrusion. Such an activity has been observed for condensin, which forms loops in mitosis, but not for cohesin. Using biochemical reconstitution, we found that single human cohesin complexes form DNA loops symmetrically at rates up to 2.1 kilo–base pairs per second. Loop formation and maintenance depend on cohesin’s ATPase activity and on NIPBL-MAU2, but not on topological entrapment of DNA by cohesin. During loop formation, cohesin and NIPBL-MAU2 reside at the base of loops, which indicates that they generate loops by extrusion. Our results show that cohesin and NIPBL-MAU2 form an active holoenzyme that interacts with DNA either pseudo-topologically or non-topologically to extrude genomic interphase DNA into loops.

Formate and potassium ions affect Escherichia coli proton ATPase activity at low pH during mixed carbon fermentation

IUBMB Life ◽  
2020 ◽  
Vol 72 (5) ◽  
pp. 915-921 ◽  
Author(s):  
Heghine Gevorgyan ◽  
Armen Trchounian ◽  
Karen Trchounian
Keyword(s):  
Escherichia Coli ◽  
Atpase Activity ◽  
Low Ph ◽  
Potassium Ions ◽  
Proton Atpase
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