scholarly journals Renal sodium-potassium adenosine triphosphatase. Optical localization and x-ray microanalysis.

1975 ◽  
Vol 23 (11) ◽  
pp. 828-839 ◽  
Author(s):  
R Beeuwkes ◽  
S Rosen
Keyword(s):  
Atpase Activity ◽  
Electron Probe ◽  
Sequential Analysis ◽  
Relative Sensitivity ◽  
Initial Reaction ◽  
Initial Product ◽  
Sodium Potassium ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of ◽  
Convoluted Tubules

The distribution of sodium-potassium adenosine triposphatase (Na-K-ATPase) activity in kidney sections has been studied by a method based on the hydrolysis of p-nitrophenyl phosphate in alkaline medium containing dimethyl sulfoxide. The products at each stage in the reaction sequence have been subjected to electron probe microanalysis. The initial product was identified as a mixture of KMgPO4 and Mg(PO4)2, and sequential analysis demonstrated the linearity of conversion of this product to a visible form. In human, rabbit and rat kidneys the distribution of activity was found to be essentially identical, with highest levels located in thick ascending limbs and distal convoluted tubules. The initial reaction was completely potassium dependent and was inhibited by ouabain in concentrations reflecting the relative sensitivity of microsomal Na-K-ATPase in each species. Measurement of initial product phosphorus by means of the electron probe is presented as a practical technique for direct quantitation of Na-K-ATPase activity in identified tubule segments.

scholarly journals The significance of inhibitor-resistant alkaline phosphatase in the cytochemical demonstration of transport adenosine triphosphatase.

1975 ◽  
Vol 23 (8) ◽  
pp. 571-574 ◽  
Author(s):  
J A Firth ◽  
B Y Marland
Keyword(s):  
Alkaline Phosphatase ◽  
Adenosine Triphosphatase ◽  
Renal Cortex ◽  
Sodium Potassium ◽  
Cytochemical Demonstration ◽  
Nitrophenyl Phosphate ◽  
Atpase Cytochemistry ◽  
Strontium Ions ◽  
Dependent Transport ◽  
Hydrolysis Of

The hydrolysis of disodium p-nitrophenyl phosphate at pH 9.0 by slices of formaldehydee-fixed rat renal cortex was investigated by colorimetric estimation of the nitrophenol liberated. It was found that three types of activity could be identified on the basis of their responses to inhibitors and cations: (a) alkaline phosphatase sensitive to inhibition by L-tetramisole; (b) potassium-dependent phosphatase, probably identifiable with the phosphatase component of sodium-potassium-dependent transport adenosine triphosphatase (?Na-K-ATPase); and (c) alkaline phosphatase insensitive to L-tetramisole. It was found that in the presence of strontium ions, as used in Na-K-ATPase cytochemistry, the activities of the second and third types of enzyme were approximately equal. The implications of these findings for the cytochemical demonstration of Na-K-ATPase are discussed.

Adenosine Receptor Modulation of Hypoxic-ischemic Injury in Striatum of Newborn Piglets

2020 ◽  
Vol 17 (4) ◽  
pp. 510-517
Author(s):  
Santiago Ortega-Gutierrez ◽  
Brandy Jones ◽  
Alan Mendez-Ruiz ◽  
Pankhil Shah ◽  
Michel T. Torbey
Keyword(s):  
Oxidative Stress ◽  
Atpase Activity ◽  
Neuronal Injury ◽  
Receptor Activation ◽  
Adult Mortality ◽  
Vehicle Group ◽  
Sodium Potassium ◽  
Receptor Modulation ◽  
A2a Receptor ◽  
Potassium Atpase

Background: Hypoxic-ischemic encephalopathy (HIE) is a major cause of pediatric and adult mortality and morbidity. Unfortunately, to date, no effective treatment has been identified. In the striatum, neuronal injury is analogous to the cellular mechanism of necrosis observed during NMethyl- D-Aspartate (NMDA) excitotoxicity. Adenosine acts as a neuromodulator in the central nervous system, the role of which relies mostly on controlling excitatory glutamatergic synapses. Objective: To examine the effect of pretreatment of SCH58261, an adenosine 2A (A2A) receptor antagonist and modulator of NMDA receptor function, following hypoxic-ischemia (HI) on sodium- potassium ATPase (Na+, K+-ATPase) activity and oxidative stress. Methods: Piglets (4-7 days old) were subjected to 30 min hypoxia and 7 min of airway occlusion producing asphyxic cardiac arrest. Groups were divided into four categories: HI samples were divided into HI-vehicle group (n = 5) and HI-A2A group (n = 5). Sham controls were divided into Sham vehicle (n = 5) and Sham A2A (n = 5) groups. Vehicle groups were pretreated with 0.9% saline, whereas A2A animals were pretreated with SCH58261 10 min prior to intervention. Striatum samples were collected 3 h post-arrest. Sodium-potassium ATPase (Na+, K+-ATPase) activity, malondialdehyde (MDA) + 4-hydroxyalkenals (4-HDA) and glutathione (GSH) levels were compared. Results: Pretreatment with SCH58261 significantly attenuated the decrease in Na+, K+-ATPase, decreased MDA+4-HDA levels and increased GSH in the HI-A2A group when compared to HIvehicle. Conclusion: A2A receptor activation may contribute to neuronal injury in newborn striatum after HI in association with decreased Na+, K+-ATPase activity and increased oxidative stress.

Catalytic Hydrolysis of 4-Nitrophenyl Phosphate by Lanthanum(III)-Hectorite

Langmuir ◽  
2003 ◽  
Vol 19 (6) ◽  
pp. 2188-2192 ◽  
Author(s):  
Steven T. Frey ◽  
Benjamin M. Hutchins ◽  
Brian J. Anderson ◽  
Teresa K. Schreiber ◽  
Michael E. Hagerman
Keyword(s):  
Catalytic Hydrolysis ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of

scholarly journals Phosphatase synthesis in Klebsiella (Aerobacter) aerogenes growing in continuous culture

1972 ◽  
Vol 127 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. G. Bolton ◽  
A. C. R. Dean
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Continuous Culture ◽  
Activity Profile ◽  
Glucose Effect ◽  
Ph Values ◽  
Nitrophenyl Phosphate ◽  
Wide Range ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

1. Phosphatase synthesis was studied in Klebsiella aerogenes grown in a wide range of continuous-culture systems. 2. Maximum acid phosphatase synthesis was associated with nutrient-limited, particularly carbohydrate-limited, growth at a relatively low rate, glucose-limited cells exhibiting the highest activity. Compared with glucose as the carbon-limiting growth material, other sugars not only altered the activity but also changed the pH–activity profile of the enzyme(s). 3. The affinity of the acid phosphatase in glucose-limited cells towards p-nitrophenyl phosphate (Km 0.25–0.43mm) was similar to that of staphylococcal acid phosphatase but was ten times greater than that of the Escherichia coli enzyme. 4. PO43−-limitation derepressed alkaline phosphatase synthesis but the amounts of activity were largely independent of the carbon source used for growth. 5. The enzymes were further differentiated by the effect of adding inhibitors (F−, PO43−) and sugars to the reaction mixture during the assays. In particular, it was shown that adding glucose, but not other sugars, stimulated the rate of hydrolysis of p-nitrophenyl phosphate by the acid phosphatase in carbohydrate-limited cells at low pH values (<4.6) but inhibited it at high pH values (>4.6). Alkaline phosphatase activity was unaffected. 6. The function of phosphatases in general is discussed and possible mechanisms for the glucose effect are outlined.

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.

Pressure Effects on the Interactions of the Sarcoplasmic Reticulum Calcium Transport Enzyme with Calcium and para-Nitrophenyl Phosphate

1987 ◽  
Vol 42 (5) ◽  
pp. 641-652 ◽  
Author(s):  
Wilhelm Hasselbach ◽  
Lore Stephan
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Transport ◽  
Activation Volume ◽  
Reaction Scheme ◽  
Pressure Effects ◽  
Calcium Dependent ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of ◽  
Sarcoplasmic Reticulum Calcium ◽  
Effect Of Hydrostatic Pressure

The effect of hydrostatic pressure on calcium dependent p-nitrophenyl phosphate hydrolysis of the sarcoplasmic reticulum calcium transport enzyme has been investigated at different degree of enzyme saturation by calcium and Mg-p-nitrophenyl phosphate to distinguish between activation and binding volumes. The enzyme saturated by both ligands displays a significant dependence of the activation volume on pressure, rising from 20 ml/mol at atmospheric pressure (0.1 MPa) to 80 ml/mol at 100 MPa. At subsaturating concentration of Mg-p-nitrophenyl phosphate an activation volume of 35 ml/mol prevails between 0.1 and 40 MPa. At subsaturating concentration of calcium the activation volume approximates 80 ml/mol in the same pressure range. The binding volume for both substrates is likewise pressure dependent falling from 20 ml/mol to 0 ml/mol for Mg-p-nitrophenyl phosphate and rising from 67 ml/mol to 155 ml/mol for calcium. The pressure dependence of activation and binding volumes is analysed on account of a simplified reaction scheme yielding activation volumes and rate constants for individual reaction steps.

Na-K-ATPase activity along the rabbit, rat, and mouse nephron

1979 ◽  
Vol 237 (2) ◽  
pp. F114-F120 ◽  
Author(s):  
A. I. Katz ◽  
A. Doucet ◽  
F. Morel
Keyword(s):  
Atpase Activity ◽  
Thick Ascending Limb ◽  
Sensitivity Limit ◽  
Henle's Loop ◽  
Collecting Tubule ◽  
Pars Recta ◽  
Hydrolysis Of ◽  
Total Enzyme

Na-K-ATPase activity along the rabbit, rat, and mouse nephron was determined with a micromethod that measures directly labeled phosphate released by the hydrolysis of [gamma-32P]ATP. Na-K-ATPase activity was highest in the rat, intermediate in the mouse, and lowest in the rabbit nephron. With the exception of rabbit cortical thick ascending limb, the enzyme profile was similar in the three species: Na-K-ATPase activity per millimeter tubule length was highest in the distal convoluted tubule and thick ascending limb of Henle's loop, intermediate in the proximal convoluted tubule, and lowest in the pars recta and collecting tubule. The enzyme was present in the thin limbs of Henle's loop, but its activity was very low and measurements were close to the sensitivity limit of the method. Both the absolute activity and the fraction of the total enzyme represented by Na-K-ATPase were severalfold higher than in kidney homogenates. Finally, the Na-K-ATPase activity measured in certain segments of the rat and rabbit nephron in this study seems sufficient to account in theory for the active component of the net sodium transport found in the corresponding region of the nephron with either in vivo or in vitro single tubule microperfusion techniques.

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