Characteristics of nucleotide-converting enzymes at muscle surfaces with special reference to ion sensitivity

1968 ◽  
Vol 46 (3) ◽  
pp. 537-547 ◽  
Author(s):  
J. F. Manery ◽  
J. R. Riordan ◽  
E. E. Dryden
Keyword(s):  
Adenylate Kinase ◽  
Inorganic Phosphate ◽  
Enzyme System ◽  
Choline Chloride ◽  
Frog Muscle ◽  
Magnesium Ions ◽  
Amp Deaminase ◽  
Ultraviolet Range ◽  
Incubation Periods ◽  
Sodium And Potassium

Spectral analyses in the ultraviolet range, paper chromatography, and determinations of the release of inorganic phosphate were used to extend the investigation of the surface enzymes (frog muscle) which catalyze the conversion of ATP→ADP→AMP→IMP. ATPase and 5′-AMP deaminase appear to adhere firmly to the muscle cell surface, even after three successive incubation periods of 4 h each, whereas the adenylate kinase is more loosely bound. The observed loss of the activity of the complete enzyme system with time was shown to be due to a suboptimal substrate concentration and not to the accumulation of products of the reaction. The AMP deaminase activity was inhibited if sodium and potassium chloride were replaced by choline chloride in the incubation media. Cation analyses of media and the determination in muscle of Na, K, water, and the sorbitol-14C space permitted a calculation of the actual intra- and extra-cellular cation concentrations. In choline-containing media the intracellular potassium was in part replaced by choline. The data indicated that the deaminase was influenced by the external, not the internal, cation concentrations. Magnesium ions stimulated the inorganic phosphate release catalyzed by ATPase and adenylate kinase but inhibited the AMP deaminase. Intact frog muscle also converted GTP, CTP, UTP, and ITP in the medium to the corresponding nucleoside monophosphate.

Influence of Ethacrynic Acid on Muscle Surface Enzymes and of Ethacrynic Acid and Ouabain on Na, K, and H2O in Frog Muscle

1972 ◽  
Vol 50 (5) ◽  
pp. 432-444 ◽  
Author(s):  
J. R. Riordan ◽  
J. F. Manery ◽  
E. E. Dryden ◽  
T. S. Still
Keyword(s):  
Adenylate Kinase ◽  
Ethacrynic Acid ◽  
Narrow Range ◽  
Total Concentration ◽  
Frog Muscle ◽  
Muscle Membrane ◽  
Amp Deaminase ◽  
Passive Permeability ◽  
Minimum Concentration ◽  
Presence And Absence

Isolated frog muscles were exposed to concentrations of ethacrynic acid (2,3-dichloro-4-(2-methylene-butyryl)phenoxyaceticacid)ranging from 10−8 to 10−2 M. The diuretic (EA) at a concentration (10−3 M) which is sufficient to markedly inhibit net Na and K movements had no effect on three muscle surface enzymes (ATPase, adenylate kinase, 5′-AMP deaminase). The minimum concentration of EA required for inhibition of Na and K movement lies within the narrow range of 0.2 × 10−3 M to 10−3 M. The degree of inhibition increased with EA concentration up to 10−2 M. Concentrations of 0.2 × 10−3 M caused some contracture of the muscles as well. EA causes an increased K loss over that caused by ouabain alone both in the presence and absence of external Na. Na concentrations are not affected. Ouabain causes increased K loss over that caused by EA alone both in the presence and absence of external Na. Frog muscle has a component of K movement (about 35% of the total concentration) dependent upon external Na. This component is distinct from the ouabain-inhibited component and equal to the EA-inhibited component. The results are consistent with inhibition of the active transport of Na and K by EA as well as by ouabain and suggest that in the presence of Ca, EA also increases the passive permeability of the muscle membrane to K.

Importance of chloride for the correction of chronic metabolic alkalosis in the rat

1987 ◽  
Vol 253 (5) ◽  
pp. F1031-F1039 ◽  
Author(s):  
B. M. Wall ◽  
G. V. Byrum ◽  
J. H. Galla ◽  
R. G. Luke
Keyword(s):  
Plasma Volume ◽  
Metabolic Alkalosis ◽  
Choline Chloride ◽  
Plasma Renin ◽  
Sodium Balance ◽  
Sprague Dawley ◽  
Volume Contraction ◽  
Chloride Depletion ◽  
Sprague Dawley Rats ◽  
Sodium And Potassium

To determine whether chloride repletion without sodium could correct chronic chloride depletion metabolic alkalosis (CDA) in Sprague-Dawley rats without volume expansion and without increasing glomerular filtration rate (GFR), CDA was generated by peritoneal dialysis (PD) against 0.15 M NaHCO3 and maintained for 7-10 days by a chloride-restricted diet supplemented with sodium and potassium salts. Control animals were dialyzed against Ringer bicarbonate. The maintenance period of chronic CDA, compared with control, was characterized by hypokalemic metabolic alkalosis (serum TCO2 31.9 +/- 0.6 vs. 23.1 +/- 0.5 meq/l, P less than 0.05), volume contraction (plasma volume 3.76 +/- 0.08 vs. 4.19 +/- 0.22 ml/100 g body wt, P less than 0.05), decreased GFR (838 +/- 84 vs. 1045 +/- 45 microliters.min-1.100 g body wt-1, P less than 0.05), increased plasma renin activity (PRA) (63 +/- 13 vs. 12 +/- 3 ng.ml-1.h-1, P less than 0.05), but unchanged plasma aldosterone concentrations (PAC) (4.1 +/- 1.0 vs. 3.4 +/- 1.6 ng/dl, P = NS). Complete correction of chronic CDA was accomplished by 24 h of ingestion of choline chloride drink, and despite negative sodium balance, neutral potassium balance, continued bicarbonate ingestion, and persistent volume contraction (plasma volume 3.76 +/- 0.08 vs. 3.73 +/- 0.12 ml/100 g body wt pre- and postcorrection, P = NS), GFR remained decreased (659 +/- 87 vs. 1,045 +/- 45 microliters.min-1.100 g body wt-1, P less than 0.05), PRA decreased (63 +/- 13 vs. 33 +/- 5 ng.ml-1.h-1, P less than 0.05), but PAC did not change (4.1 +/- 1.0 vs. 6.1 +/- 1.6 ng/dl, P = NS) after correction of CDA.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium, potassium, and intestinal transport of glucose, l-tyrosine, phosphate, and calcium

1963 ◽  
Vol 205 (1) ◽  
pp. 107-111 ◽  
Author(s):  
Harold E. Harrison ◽  
Helen C. Harrison
Keyword(s):  
Small Intestine ◽  
Calcium Transport ◽  
Inorganic Phosphate ◽  
Choline Chloride ◽  
Sodium Concentration ◽  
Phosphate Transport ◽  
Metabolic Energy ◽  
Transport Systems ◽  
Bicarbonate Buffer ◽  
Distal Small Intestine

Everted loops of rat small intestine were incubated in media varying in their concentrations of sodium and potassium. Reduction of sodium concentration was effected by substitution of choline chloride in equimolar amounts for sodium chloride in the saline-bicarbonate buffer. Concentrative transport of glucose, l-tyrosine, inorganic phosphate, and calcium was measured by determination of the final ratio of the concentrations of the solute in serosal and mucosal fluids, and the increment of the solute in serosal fluid during incubation. Ca45 was used as an indicator of calcium distribution. The glucose, l-tyrosine, and inorganic phosphate transport systems require sodium, and at a submaximal concentration of sodium an increased concentration of potassium is inhibitory. The calcium transport system does not require sodium and in loops from the distal small intestine calcium transport is enhanced by reduction of sodium concentration in the medium. It is postulated that there is a common sodium-requiring system which is necessary for the linkage of metabolic energy to glucose, amino acid, and inorganic phosphate transport.

scholarly journals Salt-Stimulated Adenosine Triphosphatases from Carrot, Beet, and Chara Australis

1967 ◽  
Vol 20 (6) ◽  
pp. 1069 ◽  
Author(s):  
MR Atkinson ◽  
GM Polya
Keyword(s):  
Fresh Water ◽  
Choline Chloride ◽  
Potassium Sulphate ◽  
Adenosine Triphosphatases ◽  
Chara Australis ◽  
Transport Atpases ◽  
Fresh Water Alga ◽  
Sodium And Potassium ◽  
Animal Transport

Soluble adenosine triphosphatases (ATPases) from carrot, beetroot, and the fresh-water alga Ohara australi8 were activated by sodium and potassium chlorides, but not by choline chloride, and were inhibited by potassium sulphate and fluoride. Ouabain was not inhibitory, and Na+-K+ synergism of the type found with animal "transport" ATPases was not observed.

Distribution of enzymes of adenylate and guanylate nucleotide metabolism in rat nephron

1982 ◽  
Vol 243 (4) ◽  
pp. F349-F355
Author(s):  
B. R. Cole ◽  
A. E. Hays ◽  
J. G. Boylan ◽  
H. B. Burch ◽  
O. H. Lowry
Keyword(s):  
Adenylate Kinase ◽  
Metabolic Pathways ◽  
High Energy ◽  
Nucleotide Metabolism ◽  
Thick Ascending Limb ◽  
Amp Deaminase ◽  
Patterns Of Distribution ◽  
Degradative Enzyme ◽  
Convoluted Tubules ◽  
Nephron Heterogeneity

In a previous study of discrete segments of rat nephron, we reported the levels of high-energy adenylate and guanylate phosphates to be highest in the distal straight and convoluted tubules. Those findings stimulated the study of the distribution of seven enzymes involved in the following metabolic pathways of these nucleotides [Formula: see text]. The patterns of distribution of enzymes in each pathway differed greatly. The phosphodiesterases, 1 and 2, were high in glomeruli and distal tubular segments and low in proximal segments. Adenylate kinase, 3, in contrast, was high in glomeruli, proximal segments, thick ascending limb of Henle, and distal convoluted tubules. Guanylate kinase levels, 4, however, were similar in all segments. The pattern of nucleosidediphosphate kinase, 5, was high in proximal convoluted, thick ascending limb, and distal convoluted tubules. The pattern of the degradative enzyme, 5'-nucleotidase, 6, whose levels were highest in proximal segments, was opposite from that of AMP deaminase, 7, highest in the distal nephrons. These dissimilar patterns underscore the extent of nephron heterogeneity.

The (Na++K+) activated enzyme system and its relationship to transport of sodium and potassium

1974 ◽  
Vol 7 (3) ◽  
pp. 401-434 ◽  
Author(s):  
Jens Chr. Skou
Keyword(s):  
Transport System ◽  
Enzyme System ◽  
Membrane Bound ◽  
Hydrolysis Of ◽  
Sodium And Potassium

It seems to be the membrane bound (Na++K+)-activated enzyme system which transforms the energy from a hydrolysis of ATP into a vectorial movement of sodium out and potassium into the cell against electrochemical gradients, i.e. this systems seems to be the transport system for sodium and potassium (see, for example, review by Skou, 1972; Hokin & Dahl, 1972).

THE DESTRUCTION OF O,O-DIETHYL-S-2-DIETHYLAMINOETHYL PHOSPHOROTHIOLATE BY LIVER MICROSOMES

1959 ◽  
Vol 37 (1) ◽  
pp. 297-305
Author(s):  
J. F. Scaife ◽  
D. H. Campbell
Keyword(s):  
Guinea Pig ◽  
Enzymatic Activity ◽  
Inorganic Phosphate ◽  
Enzyme System ◽  
Liver Microsomes ◽  
Rat Plasma ◽  
Fresh Tissue ◽  
Sh Groups ◽  
Diisopropyl Phosphorofluoridate ◽  
Liver Homogenates

Liver homogenates prepared from the rat, rabbit, mouse, and guinea pig possess an enzyme system capable of destroying O,O-diethyl-S-2-diethylaminoethyl phosphorothiolate at the rate of 150 to 200 μg/hr/g of fresh tissue. The homogenates prepared from the pig, dog, cow, and frog destroyed this compound at a rate of 50 to 100 μg/hr/g, but those prepared from man and the cat possessed negligible activity. Rat plasma, brain, kidney, diaphragm, whole gut, and spleen also possessed little or no activity. This enzyme system is located in the microsomes, disruption of which is accompanied by loss of enzymatic activity. The activity is dependent upon oxygen, inorganic phosphate, and diphosphopyridine nucleotide. Inhibitor studies indicate that enzymic SH-groups are necessary. The enzyme has no action on diisopropyl phosphorofluoridate, isosystox, or tetraethyl pyrophosphate, although these compounds are rapidly destroyed by the liver.

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