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 dicyclohexylcarbodiimide-binding protein of Aspergillus nidulans has been identified as the smallest subunit of the mitochondrial ATPase complex, and has a molecular weight of approximately 8000. It is extractable from whole mitochondria and from the purified enzyme in neutral chloroform/methanol, contains 30% polar amino acids, and the N-terminal amino acid has been identified as tyrosine. Using a double-labelling technique in the absence and presence of cycloheximide, followed by immunoprecipitation of the enzyme complex with antiserum against Neuospora crassa F1 ATPase, it has been shown that this subunit is synthesized on cytoplasmic ribosomes.
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PMID:Mitochondrial ATPase complex of Aspergillus nidulans and the dicyclohexylcarbodiimide-binding protein. 15 78

During the inactivation of the nucleotide-free F1-ATPase at pH 7.0, by p-fluorosulfonyl[14C]benzoyl-5'-adenosine ([14C]FSBA) in the presence of 20% glycerol, about 4.5 g atoms of 14C are incorporated/350,000 g of enzyme. Isolation of the subunits has shown: (a) over 90% of the incorporated label is associated with the alpha and beta subunits; (b) the amount of label incorporated into the alpha subunit is about 0.5 g atoms/mol which is nonspecifically associated with a number of tyrosine and lysine residues; (c) the amount of radioactivity incorporated into the beta subunit is about 0.9 g atoms/mol which correlates with the degree of inactivation of the enzyme and resides on a single tyrosine residue; (d) up to 2.2 mol of alpha subunit have been isolated from each mole of inactivated enzyme; and (e) about 2 mol of beta subunit have been isolated from each mole of inactivated enzyme. These results account for the incorporation of 4.5 g atoms of 14C which are incorporated/mol of ATPase during inactivation if there are three copies each of the alpha and beta subunit present in the enzyme. It has also been shown that 4-chloro-7-nitrobenzofurazan (NBD-Cl) and FSBA react with different tyrosine residues when they inactivate the ATPase. In addition, it has been shown that the ATPase inactivated with FSBA retains the capacity to bind up to 2.2 mol of [14C]ADP/350,000 g of enzyme.
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PMID:On the subunit stoichiometry of the F1-ATPase and the sites in it that react specifically with p-fluorosulfonylbenzoyl-5'-adenosine. 15 96

Ultrafiltered fur seal muscle hydrolysate was divided into eleven fractions by gel filtration on Sephadex G-15. One of the fractions (Fraction G9) accelerated the ATPase activity of carp myosin B to a rate about two-fold faster than that of the control. Fraction G9 showed a single ninhydrin spot in its silica gel thin layer chromatograph, and gave a positive test for tryptophan by the p-dimethylaminobenzaldehyde method, while tests for tyrosine, and for arginine were negative. The ion exchange amino acid analysis of its acid hydrolysate showed a predominant content of lysine, nearly equivalent to the amount of tryptophan determined from its UV absorbancy and the p-dimethylaminobenzaldehyde method. The N-terminal amino acid analysis gave di-DNP-Lys as the sole DNP-amino acid. The structure of the ATPase accelerating peptide fraction, Fraction G9, was deduced to be Lys-Trp.
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PMID:Nature of adenosine triphosphatase accelerating peptide from hydrolysate of fur seal muscle. 16 Sep 12

Neurochemical and psychopharmacological studies of rats were designed to examine four hypotheses which have been proposed to account for the development of behavioral tolerance to the anticholinesterase, diisopropyl fluorophosphate (DFP). The fact that the activity of the enzymes, adenosine triphosphatase, alkaline phosphatase and cytochrome oxidase, did not change concomitantly with behavioral measures during chronic treatment with DFP suggests that nonspecific metabolic changes are unlikely mechanisms of behavioral tolerance. Similarly, a lack of change in choline acetylase activity coupled with constantly high acetylcholine levels (140%) and low cholinesterase activity (28.5%) tends to eliminate end-product inhibition of acetylcholine synthesis as a primary mechanism of tolerance to DFP. Alpha-Methyl-p-tyrosine in doses to 150 mg/kg affected the behaviors of control and DFP-treated rats to a comparable degree, offering no support for the hypothesis that a redundant adrenergic system may replace the cholinergic system during the development of tolerance to DFP. In contrast to these various negative findings, pilocarpine was less effective in suppressing the responding of rats tolerant to DFP than that of control subjects. This confirms other evidence indicating that a decreased sensitivity of cholinergic (muscarinic) receptors is one mechanism underlying the development of tolerance to DFP.
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PMID:Experimental tests of hypotheses about neurochemical mechanisms underlying behavioral tolerance to the anticholinesterase, diisopropyl fluorophosphate. 16 30

A study has been made of the progress of involution of the mouse and rat mammary gland using histologic, electron microscopic, histochemical and autoradiographic methods. Particular emphasis has been placed on the morphology, metabolic alterations and activities of histochemically identifiable enzymes, and on the pharmacologic effects of lactation inhibiting agents and cytostatic drugs on lactation and involution. In order to allow a systematic investigation, involution was initiated in rats and mice by ligation of individual gland ducts at various time intervals. Both lactating glands and glands in different phases of involution were thus available in a given animal. The most important observation was that involution, which altogether takes approximately 2 weeks to be complete, involves a three-phase process, each phase being clearly distinguishable by morphologic and histochemical criteria. The first phase comprises approximately 4 days during which production of milk may be reinitiated. The second phase starts on day 5 of involution and constitutes the period of involution per se characterized by appreciable parenchymal cell degradation. The third phase, which starts around day 10, is the period of reorganization to the resting mammary gland. Early in the first phase of involution, substantial alveolar enlargement due to engorgement with milk, together with epithelial flattening, are prominent features. By day 3, the glandular contents decrease again in volume, the number of glandular cells and the constituent cytoplasmic organelles remaining unchanged during this period, except for the diminished appearance of fat droplets. In addition to normal appearing vacuoles with only occasional or sparse protein granules, giant vacuoles containing, in part, several hundred casein granules are found. Their formation appears to be due to increased stacking of granules in distended vacuoles prior to dissociation from the Golgi apparatus. In addition, however, the enhanced reactions of alP (alkaline phosphatase) and ATPase, which are found in the apical plasmalemma, are suggestive of resorptive activities. Protein particles absorbed from the glandular lumen equally appear to have a capacity for fusing into large vacuoles. The large protein granule-containing vacuoles regularly exhibit intense beta-Glu activity. This enzyme would appear to contribute actively to the degradation of excess milk during the first phase of involution. Autoradiographic studies reveal that the synthesis and release of proteins into the secretion is maintained for 3 days. While 3H-tyrosine uptake by the alveolar cells continues unchanged, the incorporation of 3H-palmitic acid into glandular lipoids, and of 3H-fucose into glandular polysaccharides is virtually blocked completely. An immediate reaction of the lipoid metabolism is also indicated by the decrease in 3HBDH activity on the first day of involution...
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PMID:[Involution of the mammary gland. Enzyme histochemistry, elektron microscopy and radioautography (author's transl)]. 18 47

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

1. The interaction of NAD+, NADH and various nucleotide analogues with pig kidney alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum) EC 3.1.3.1) has been investigated by kinetic means. Some inhibitors act uncompetitively whereas others markedly increase the slopes of double reciprocal plots suggesting they have some affinity for the free enzyme. 2. The compounds seem to bind to alkaline phosphatase through interactions of their bases with a relatively non-specific region of the enzyme, although it is likely that for those nucleotides having some affinity for the free enzyme there is some attraction between the pyrophosphate backbone and the active site. 3. From studies of the effect of NAD+ and NADH on ATPase activity it was concluded that the substrate inhibition that is characteristic of the ATPase activity of alkaline phosphatase originates from binding of ATP to the site assumed to exist for NAD+ and NADH. The potentiation of NAD+-inhibition of ATPase activity by Mg-2+ is probably a result of the depletion of [ATP-4-] the true substrate. The depletion allows NAD+ to complete more effectively for the active site. 4. Binding of NADH is favoured by protonation of an enzymic group with a pK of approx. 9.0 belonging possibly to a tyrosine residue or a zinc hydrate. 5. A large entropy decrease was found to accompany the binding of NAD+ and NADH to alkaline phosphatase. This may be further evidence of an "induced-fit" mechanism previously suspected because of the synergistic inhibitory effects of adenosine and nicotinamide.
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PMID:Nicotinamide-adenine dinucleotide inhibition of pig kidney alkaline phosphatase. 23 67

1. Evidence is presented which indicates that inactivation of the mitochondrial ATPase from bovine heart by the reagent 4-chloro-7-nitrobenzofurazan results from modification of one tyrosine residue per enzyme molecule. Activity can be restored by a variety of sulphydryl reagents. 2. In sodium dodecyl sulphate, the nitrogenzofurazan group on tyrosine is transfered to newly exposed sulphydryl groups on the enzyme. 3. The rate of transfer of the nitrobenzofurazan moiety from theenzyme to sulphydryl compounds is compared with that for transfer from the model compound N-acetyl-tyrosine-0(7-nitrobenzo-furazan) ethyl ester, the synthesis and properties of which are also described. 4. The ligands ATP and ADP exert a protective effect on the rate of reaction between the mitochondrial ATPase and 4-chloro-7-nitrobenzofurazan. The variation in rate of this reaction with change in pH has also been examined and a pKa of 9.5 estimated for the tyrosine residue. 5. The modification does not prevent substrate binding as judged by changes in the fluorescence of aurovertin, an antibiotic with specific affinity for mitochondiral ATPases. 6. When the ATPase activity of submitochondrial particles is inhibited by 4-chloro-7-nitrobenzo-furazan, there is a parallel decrease in the extent of the energy-linked fluorescence enhancement of 1-anilino-naphthalene-8-sulphonate induced by ATP hydrolysis. Both ATPase activity and the fluorescence enhancement are restored by sluphydryl reagents.
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PMID:The mitochondrial ATPase. Evidence for a single essential tyrosine residue. 23 39

1. When mitochondrial ATPase, which has been modified on a single tyrosine residue by 4-chloro-7-nitrobenzofurazan, is incubated at pH 9.0, the 7-nitrobenzofurazan group undergoes an intramolecular transfer to a nitrogen residue. The rate of this transfer is sensitive to the binding of adenine nucleotides to the enzyme. The resulting N-nitrobenzofurazan ATPase has little or no activity. 2. The fluorescence of the N-nitrobenzofurazan group in the modified ATPase is quenched on binding of ADP. 3. Electrophoresis of the modified enzyme in sodium dodecyl sulphate on a 10% polyacrylamide gel shows that the fluorescence of the N-nitrobenzofurazan chromophore is exclusively in the beta subunit. 4. The rate of transfer of the nitrobenzofurazan group from tyrosyl oxygen to nitrogen on the enzyme is compared with the rate of transfer between model compounds. 5. The interaction of the N-nitrobenzofurazan ATPase with aurovertin is reported.
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PMID:The mitochondrial ATPase. Selective modification of a nitrogen residue in the beta subunit. 23 40

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


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