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)

The tritiated cardiotonic steroids, ouabain, digitoxin, and digitoxigenin are shown to photolabel the large polypeptide but not the glycoprotein or proteolipid component of the (Na+ + K+)-ATPase when they are bound to the inhibitory site and exposed to light of 220 or 254 nm. The extent of photolabeling is low, less than 1%, and is limited by photocross-linking of the enzyme. The mechanism of photoincorporation does not appear to be either photolysis of the lactone ring in ouabain or photolysis of tryptophan or tyrosine residues in the polypeptide.
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PMID:Direct photoaffinity labeling of the primary region of the ouabain binding site of (Na+ + K+)-ATPase with [3H]ouabain, [3H]digitoxin and [3H]digitoxigenin. 22 26

We propose that the UGA terminator regularly occurs as a tryptophan codon in yeast mitochondrial DNA. This conclusion is based on the sequence analysis of mitochondrial DNA regions coding for structural genes of cytochrome b, cytochrome oxidase, and the ATPase.
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PMID:Use of the UGA terminator as a tryptophan codon in yeast mitochondria. 22 81

The interaction of myosin subfragment-1 (S-1) with 4,4'-bis(1-anilinonaphthalene 8-sulfonate) (bis-ANS) has been studied by monitoring the fluorescence of the latter when the two components form a complex. Because ATP and ATP analogs partially displace complexed bis-ANS it has also been possible to study interactions of S-1 and nucleotides by using the displacement effect. Approximate values of the parameters of these various interactions have been measured. Some possible applications of bis-ANS have been explored. For example, it provides a very convenient method for obtaining the Michaelis constant, Km, in steady-state S-1 nucleoside triphosphatase; this particular application has also provided some evidence for inferring that in Ca2+ (but not in Mg2+) adenosinetriphosphatase (ATP phosphohydrolase, EC 3.6.1.3) S-1 behaves like a mixture of two components, each with its own Km. Clear energy transfer occurs between tryptophan residues and bound bis-ANS. The fluorescence also suggests that S-1 undergoes some slow relaxations following substrate binding.
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PMID:4,4'-Bis (1-anilinonaphthalene 8-sulfonate) (bis-ANS): a new probe of the active site of myosin. 26 28

A histochemical and autoradiographic study of the lining intestinal epithelium of the snake Xenodon merremii is reported. The absorptive cells present neutral polysaccharides, arginine, tyrosine, tryptophan, cysteine, alkaline phosphatase, acid phosphatase, ATPase, AMPase, esterase and RNA. There are histochemical differences between the goblet cells of the small and of the large intestine. Whereas in the former predominates the neutral polysaccharides and are found arginine, tyrosine, tryptophan and cysteine, in the latter predominates the sulfated polysaccharides (confirmed by the uptake of radioactive sulfur) and no amino acids were found.
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PMID:Histochemical (polysaccharides, proteins, nucleic acids and enzymes) and autoradiographic (incorporation of 35S labelled sodium sulfate) study of the epithelial intestinal cells of Xenodon merremii Wagler, 1824 (Ophidia). 40 42

The ATP-energy transducing system in membranes of Escherichia coli is inhibited by dicyclohexylcarbodiimide. The protein component of this complex with which carbodiimides covalently react to inhibit function was previously identified by labeling wild type and dicyclohexylcarbodiimide-resistant mutants with dicyclohexyl[14C]carbodiimide (Fillingame, R. H. (1975) J. Bacteriol. 124, 870-883). This specific carbodiimide-reactive protein has now been purified. The protein was extracted from the membrane with chloroform:methanol and chromatographed on DEAE-cellulose and hydroxypropyl Spehadex G-50 in this sulvent mixture. The resultant 700-fold purification yielded a protein that was homogeneous on dodecyl sulfate-acrylamide gel electrophoresis and virtually free of phospholipid. It remained soluble in neutral chloroform:methanol throughout the purification procedure. The amino acid composition of the purified protein was extraordinary in that only 16% of the amino acids present could be considered polar. Histidine, serine, cysteine, and tryptophan were not found. Abnormally high contents of methionine, glycine, alanine, and leucine were present. One mole of lysine and threonine were found/mole of dicyclohexyl[14C]carbodiimide bound. The minimum molecular weight based on the amino acid composition was 8400. The specific carbodiimide-reactive protein has also been purified without prior modification by dicyclohexylcarbodiimide. The unmodified protein eluted from DEAE-cellulose at a higher salt concentration than the dicyclohexylcarbodiimide-modified form, which suggested that the reaction with the carbodiimide neutralized the negative charge. Only one-third of the total carbodiimide-reactive protein in the membrane was modified by dicyclohexylcarbodiimide under conditions which maximally inhibited adenosine triphosphatase activity. These results rais the possibility that the carbodiimide-reactive protein may be present as an oligomer in the energy-transducing complex. The purification of the unmodified carbodiimide-reactive protein should permit assessment of tis biological function, particularly its role in the protein-translocation process that is catalyzed by this energy-transducing complex.
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PMID:Purification of the carbodiimide-reactive protein component of the ATP energy-transducing system of Escherichia coli. 78 71

The hormone serotonin (5-hydroxytryptamine) has been implicated as the cause of the diarrhea seen in many patients with the carcinoid syndrome. To determine whether serotonin is an intestinal secretagogue, the effect of serotonin on intestinal water and electrolyte transport was evaluated in the rabbit. Two weeks of daily subcutaneous injection of serotonin suspended in oil resulted in a blood serotonin level elevated to twice that of controls. Intestinal transport was studied in vivo by a perfusion technique. Serotonin treatment resulted in ileal secretion and decreased mid-jejunal absorption of water and electrolytes but did not effect water absorption in the proximal jejunum or colon. Intestinal absorption of D-glucose and the amino acid L-tryptophan and glucose-dependent water and electrolyte absorption were normal in serotonin-treated animals. Serotonin-induced ileal secretion was reversed by methysergide, a peripheral antagonist of serotonin action. No alterations in intestinal histology or permeability occurred in serotonin-treated animals. Serotonin-induced intestinal secretion was not associated with alterations in the activities of intestinal mucosal adenylate cyclase, cyclic nucleotide phosphodiesterase, or Na-K-ATPase.
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PMID:Effect of serotonin treatment on intestinal transport in the rabbit. 83 7

Differences exist in the coupling of energy to transport of glycine and phenylalanine in aerobically grown cells of Escherichia coli. Energy derived from respiration, although involved in both uptake systems, is not employed identically as shown by kinetic effects of cyanide and anoxia and by temperature dependencies. Additional evidence for aerobic differences was provided by the effects of azide which greatly decreased initial rates of uptake of glycine but not phenylalanine. The effect on glycine uptake was not due to uncoupling of oxidative phosphorylation or to a decrease in respiration rate. Evidence for anaerobic differences was provided by the addition of either glucose or ferricyanide to cell suspensions containing glycerol, thereby maintaining anoxic uptake of phenylalanine, but not glycine, at the aerobic level. Ferricyanide stimulation required a functional Ca, Mg-adenosine 5'-triphosphatase and involved cell metabolism. Ferricyanide was also found to produce differential stimulation of other amino acid transport systems; tyrosine, tryptophan and leucine uptakes were stimulated whereas those for alanine, proline, threonine, and glutamine were relatively unaffected.
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PMID:Differences in coupling of energy to glycine and phenylalanine transport in aerobically grown Escherichia coli. 109 78

The effects of 16 group-specific, amino acid-modifying agents were tested on ouabain binding, catalytical activity of membrane-bound (rat brain microsomal), sodium dodecyl sulfate-treated Na+,K(+)-ATPase, and Na+,K(+)-pump activity in intact muscle cells. With few exceptions, the potency of various tryptophan, tyrosine, histidine, amino, and carboxy group-oriented drugs to suppress ouabain binding and Na+,K(+)-ATPase activity correlated with inhibition of the Na+,K(+)-pump electrogenic effect. ATP hydrolysis was more sensitive to inhibition elicited by chemical modification than ouabain binding (membrane-bound or isolated enzyme) and than Na+,K(+)-pump activity. The efficiency of various drugs belonging to the same "specificity" group differed markedly. Tyrosine-oriented tetranitromethane was the only reagent that interfered directly with the cardiac receptor binding site as its inhibition of ouabain binding was completely protected by ouabagenin preincubation. The inhibition elicited by all other reagents was not, or only partially, protected by ouabagenin. It is surprising that agents like diethyl pyrocarbonate (histidine groups) or butanedione (arginine groups), whose action should be oriented to amino acids not involved in the putative ouabain binding site (represented by the -Glu-Tyr-Thr-Trp-Leu-Glu- sequence), are equally effective as agents acting on amino acids present directly in the ouabain binding site. These results support the proposal of long-distance regulation of Na+,K(+)-ATPase active sites.
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PMID:Ouabain binding, ATP hydrolysis, and Na+,K(+)-pump activity during chemical modification of brain and muscle Na+,K(+)-ATPase. 131 Jul 17

The plasma membrane of Schizosaccharomyces pombe contains an H(+)-ATPase similar to the cation transport ATPases of other eukaryotic organisms. The fluorescence excitation and emission spectra of the purified H(+)-ATPase are characteristic of tryptophan residues. pH reduction from 7.5 to 5.7 produces a 4% decrease in fluorescence intensity, while a further reduction to pH 5.0 leads to an increase of fluorescence. A close correlation is observed between the pH dependence of the intrinsic fluorescence and the pH dependence of (i) ATPase activity, (ii) the fluorescence of Tb-formycin triphosphate bound to the active site, and (iii) inhibition by vanadate of ATPase activity. It is proposed that the effect of pH on intrinsic fluorescence reveals the existence of an H+ induced conformational change of the H(+)-ATPase similar to the E1----E2 transition of the other plasma membrane cation transport ATPases.
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PMID:The yeast plasma membrane H(+)-ATPase. An essential change of conformation triggered by H+. 131 Sep 80

Serum, liver and brain tryptophan concentrations and brain Na+K(+)-ATPase activity were studied in streptozotocin diabetic rats after an acute tryptophan load. Results show that tryptophan administration in the experimental diabetic group produces a generalized fall in tryptophan uptake in all the brain regions studied, though it does not increase serum and hepatic tryptophan concentrations. These parameters are normalized in insulin-treated diabetic rats. With regard to Na+K(+)-ATPase, diabetic animals showed a diminished and unchanged activity; whereas, the other two experimental groups showed a gradual decrease and a negative correlation with brain tryptophan uptake.
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PMID:Brain tryptophan uptake and sodium-potassium ATPase activity in long-term streptozotocin diabetic rats. 132 Feb 15


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