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)

In a unique Chinese hamster mutant, Gal-32, the mitochondrially encoded subunits of cytochrome c oxidase (CO I, II, III) and NADH dehydrogenase (ND 1-6) are greatly decreased while other mitochondrially synthesized proteins, such as ATPase subunits 6 and 8, are less affected. Pulse-chase experiments with [35S]methionine demonstrated that the reduced amounts of CO I and ND 5 subunits in Gal-32 are not the result of more rapid protein degradation. No differences in sizes of mtRNAs were detected between wild type and mutant using Northern blotting. The steady state levels of both heavy and light strand mtDNA transcripts were elevated in Gal-32: CO I mRNA was 1.5-fold higher in the mutant than in the wild type; ND 5 mRNA was 1.9-fold higher; ND 6 precursor RNAs were 1.4-fold higher and ATPase 6 and 8 mRNA (a single transcript) was 2.7-fold higher. Thus, the amounts of translation products are roughly correlated with the levels of mRNAs. The reduced levels of mitochondrially synthesized proteins in Gal-32 are the result of decreased translation of specific mRNAs, not increased degradation of mtRNAs.
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PMID:Elevated mitochondrial RNA in a Chinese hamster mutant deficient in the mitochondrially encoded subunits of NADH dehydrogenase and cytochrome c oxidase. 169 38

Endogenous circulating digoxin-like immunoreactive factors (DLIF) are known to cross-react with antibodies to digoxin and to inhibit Na+/K(+)-transporting ATPase (Na+K+ATPase; EC 3.6.1.37). Moreover, increasing the immunoassay temperature from 4 to 37 degrees C markedly decreases DLIF from human cord serum. We tested several compounds, including hormonal steroids, bile salts, lipids, and methionine-enkephalin, for their ability to cross-react with two commercially available 125I digoxin RIAs, to inhibit porcine Na+K+ATPase, and to see whether they present the same incubation temperature dependence as human cord serum. Except for methionine-enkephalin, all compounds were inhibitors of Na+K+ATPase in the range of 1-10 mmol/L. Progesterone exhibited the highest cross-reactivity in the two RIAs. The apparent digoxin immunoreactivity for the majority of the cross-reacting steroids, bile salts, and linoleic acid was markedly decreased by increasing the incubation temperature from 4 to 37 degrees C, whereas estriol, pregnanediol, and nonspecific compounds (e.g., ethanol, human serum albumin) did not appear to be temperature-sensitive. Both lysophosphatidyl lipids gave an increased apparent digoxin concentration with increasing incubation temperature. Our data suggest that numerous weakly cross-reactive compounds can parallel the response of human cord serum. However, the temperature-dependent effect could be an additional criterion for identifying DLIF.
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PMID:Temperature-dependent immunoreactive assay to screen for digoxin-like immunoreactive factor(s). 171 32

Effect of protein deficient diet on hepatic plasma membrane fluidity has been studied in rats using (i) steady state fluorescence polarization and anisotropy, (ii) phospholipid and cholesterol contents, (iii) phospholipid fatty acid composition, (iv) turnover of phosphatidyl choline (PC), and (v) activities of membrane-bound enzymes as parameters and rats fed casein (20%) diet as standard group. A significant increase in steady state fluorescence and anisotropy values was registered in the deficient group, indicating increased resistance and hence decrease in fluidity of the plasma membrane. Supplementation of the diet with lysine and threonine improved these values, thereby suggesting the significance of diet for membrane fluidity. Simultaneous significant alterations in other parameters, viz. (i) decrease in PC, PE and free cholesterol and increase in esterified cholesterol contents, (ii) decrease in unsaturation of fatty acids of PC, (iii) decrease in incorporation of NaH2 32PO4, [CH3-14C]choline and [CH3-14C]methionine into plasma membrane PC, and (iv) decrease in activities of plasma membrane 5'-nucleotidase and phosphodiesterase along with increase of (Na(+)-K+)ATPase and adenyl cyclase, were observed in the deficient group which on supplementation with lysine and threonine showed improvement over alterations.
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PMID:Hepatic plasma membrane fluidity and dietary proteins. 175 32

Vacuolar proton pumps acidify several intracellular membrane compartments in the endocytic pathway. We have examined the distribution of the vacuolar H+ ATPase in LLC-PK1 cells and the structure of the biosynthetically labeled enzyme in membrane fractions enriched for endosomes or lysosomes. LLC-PK1 cells were allowed to internalize cytochrome c-coated colloidal gold as a marker for endocytic compartments. Proton pumps were identified in these cells by staining the cells with a monoclonal antibody against the vacuolar pump detected with either immunogold or immunoperoxidase techniques. H+ ATPase labeling was seen on structures resembling endosomes and lysosomes, but not on Golgi or plasma membrane. To examine the structure of the H+ ATPase in these compartments, we labeled LLC-PK1 cells for 24 h with [35S]methionine and used a Percoll gradient to obtain fractions enriched for endosomes or lysosomes. H+ ATPase immunoprecipitated from both fractions with monoclonal anti-H+ ATPase antibodies had labeled polypeptides of 70, 56, and 31 kDa. On two-dimensional gels, a comparison of the H+ ATPase from the endosomal and lysosomal fractions revealed that the 70-, 56-, and 31-kDa subunits were similar in both fractions. The results show that the vacuolar H+ ATPase in these cells is distributed primarily in endosomes and lysosomes and that the structure of the enzyme is similar in both compartments.
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PMID:Distribution and structure of the vacuolar H+ ATPase in endosomes and lysosomes from LLC-PK1 cells. 182 36

Ca2+ binding to fast skeletal muscle troponin C reincorporated into troponin C-depleted (CDTA-treated) myofibrils has been measured directly by using 45Ca and indirectly by using a fluorescent probe. Direct Ca2(+)-binding measurements have shown that the Ca2+ affinity of the low-affinity sites is enhanced in the absence of ATP and conversely reduced when myosin is selectively extracted from myofibrils, compared to the Ca2+ affinity in the presence of ATP. Fluorescence intensity changes of a dansylaziridine label at the Met-25 residue of troponin C have shown the same Ca2(+)-sensitivity whether or not ATP is present, while much lower Ca2(+)-sensitivity is seen in the myosin-extracted myofibrils. Since the Met-25 residue is in the amino terminal side alpha-helix of Ca2(+)-binding site I and far from Ca2(+)-binding site II in the primary structure, Ca2+ binding to site II has been evaluated by assuming that the fluorescence change monitors Ca2+ binding to site I alone. Ca2+ binding to site II thus estimated has shown high positive cooperativity only in the presence of ATP and has been found to be nearly proportional to the activation of myofibrillar ATPase, suggesting that Ca2(+)-binding site II is directly involved in the activation of myofibrillar ATPase activity. On the other hand, Ca2(+)-binding site I has been suggested to regulate the interaction of weakly binding cross-bridges with the thin filament, since the fluorescence change in the presence of ATP is saturated at the free Ca2+ concentration required for the activation of myofibrillar ATPase.
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PMID:Effect of myosin cross-bridge interaction with actin on the Ca2(+)-binding properties of troponin C in fast skeletal myofibrils. 182 77

Preliminary studies on yeast peroxisomes have suggested that the membrane of these organelles may contain a proton-pumping ATPase. It has been reported that peroxisome-associated activity is similar to the F0-F1 mitochondrial type ATPase in its sensitivity to azide at pH 9.0, but characteristics of the plasma membrane type ATPase are also evident in peroxisomal preparations in that they exhibit pH 6.5 activity that is sensitive to vanadate. A comparative study of the prominent organellar ATPase activities was undertaken as a probe into the existence of an enzyme that is unique to the peroxisome, and biochemical properties of yeast mitochondrial, plasma membrane, together with peroxisomally-associated H(+)-ATPases are presented. Enzyme marker analysis of sucrose gradient fractions revealed a high degree of correlation between the amount of azide-sensitive pH 9.0 ATPase activity and that of the mitochondrial membrane marker, cytochrome c oxidase, in peroxisomal preparations. Purified mitochondrial and peroxisomally-associated activities were highly sensitive to the presence of sodium azide, N,N' -dicyclohexylcarbodiimide (DCCD) and venturicidin when measured at pH 9.0. Comparisons of peroxisomal activities with those of the purified plasma membrane at pH 6.0 in the presence of azide showed similar sensitivity profiles with respect to inhibitors of yeast plasma membrane ATPases such as vanadate and p-chloromercuriphenyl-sulfonic acid (CMP). Purified peroxisomal membranes, furthermore, reacted with antibody to the mitochondrial F1 subunit (as revealed by Western blot analysis), and [35S] methionine-labeled, glucose-grown cells processed with unlabeled methanol-grown cells, yielded sucrose gradient fractions that were radioactive in bands that were also recognized by F1 antibody. Isolated fractions in these experiments had similar ratios of cpm:pH 9.0 ATPase activities, suggesting that this activity is mitochondrial in origin. The data presented for the characteristics of the peroxisomally-associated activity strongly suggest that the majority of the ATPase activity found in peroxisomal preparations is derived from other organelles.
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PMID:ATPase activities in peroxisome-proliferating yeast. 182 38

The subunit analogous to the d-subunit of ATP synthase from bovine heart mitochondria was isolated from the purified yeast enzyme. Partial protein sequences were determined by direct methods. From this information, two oligonucleotide probes were constructed and used for screening a DNA genomic bank of Saccharomyces cerevisiae. The sequence of yeast subunit d was deduced from the DNA sequence of ATP7 gene. Mature yeast subunit d is 173 amino acids long. Its NH2-terminal serine is blocked by an N-acetyl group, and the protein has no processed NH2-terminal sequence other than the removal of the initiator methionine. The protein is predominantly hydrophilic. The amino acid sequence is 22% identical and 44% homologous to bovine subunit d. A null mutant was constructed. The mutant strain was unable to grow on glycerol medium. The mutant mitochondria had no detectable oligomycin-sensitive ATPase activity, and the catalytic sector F1 was loosely bound to the membranous part. The mutant mitochondria did not contain subunit d, and the mitochondrially encoded hydrophobic subunit 6 was not present.
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PMID:ATP synthase of yeast mitochondria. Characterization of subunit d and sequence analysis of the structural gene ATP7. 183 57

The Ca2+/Mg2+ ATPase, which is activated by millimolar concentrations of Ca2+ or Mg2+, was solubilized from rat heart plasma membrane by employing lysophosphatidylcholine, CHAPS, NaI, EDTA and Tris-HCl at pH 7.4. The enzyme was purified by sucrose density gradient, Affi-Gel Blue column and Sepharose 6B column chromatography. The purified enzyme was seen as a single peptide band in the sodium dodecyl sulfate polyacrylamide gel electrophoresis with a molecular weight of about 90,000. The apparent molecular weight of the holoenzyme as determined under non-dissociating conditions by gel filtration on Sepharose 6B column was about 180,000 indicating two subunits. The enzyme was insensitive to ouabain, verapamil, vanadate, oligomycin, N,N-dicyclohexylcarbodiimide and NaN3, but was markedly inhibited by 20 microM gramicidin S and 50 microM trifluoperazine. Analysis of the purified Ca2+/Mg2+ ATPase revealed the presence of 17 amino acids where leucine, glutamic acid and aspartic acid were the major components and histidine, cysteine and methionine were the minor components. The purified enzyme was associated with 19.7 mumol phospholipid/mg protein which was 60 times higher than the phospholipid content in plasma membrane. The cholesterol content in the purified enzyme preparation was 0.75 mumol/mg protein and this represented an 8-fold enrichment over plasma membrane. The glycoprotein nature of the enzyme was evident from the positive periodic acid-Schiff staining of the purified Ca2+/Mg2+ ATPase in the sodium dodecyl sulfate polyacrylamide gel. The polysaccharide content of the enzyme was enriched 8-fold over plasma membrane; neuraminidase treatment decreased the polysaccharide content. Concanavalin A prevented the ATP-dependent inactivation of the purified Ca2+/Mg2+ ATPase and was found to bind to the purified enzyme with a KD of 576 nM and Bmax of 4.52 nmol/mg protein. The results indicate that Ca2+/Mg2+ ATPase is a glycoprotein and contains a large amount of lipids.
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PMID:Purification and composition of Ca2+/Mg2+ ATPase from rat heart plasma membrane. 183 89

The rat gastric H+,K(+)-ATPase alpha subunit gene was cloned and the nucleotide sequence of its 5'-upstream region was determined. Sequence comparison with the corresponding part of the human gene indicated the presence of highly conserved regions which may be important for specific transcription of the alpha subunit in gastric parietal cells. The amino-terminal sequence (Met-Gly-Lys-Ala-Glu-) of the rat enzyme was similar to those of the pig and human enzymes. The gene organization of the rat enzyme was also similar to that of the human gene: introns 1, 2 and 9 were located in exactly the same positions as those in the human gene, and, as in the latter, exon 6 was not separated by an intron. The sequences of introns 1 and 2 were highly conserved among the rat, human and pig genes, but were entirely different from those of Na+,K(+)-ATPase catalytic subunit genes. Northern blot hybridization indicated that the gene was transcribed only in gastric mucosa.
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PMID:Control region and gastric specific transcription of the rat H+,K(+)-ATPase alpha subunit gene. 184 40

Two open reading frames on a 3.7-kb BglII-XbaI fragment which encodes the Staphylococcus aureus cadA cadmium (and zinc) resistance determinant of plasmid pI258 were identified (G. Nucifora, L. Chu, T. K. Misra, and S. Silver, Proc. Natl. Acad. Sci. USA 86:3544-3548, 1989). The [35S]methionine-labelled protein products of the 727-amino-acid CadA ATPase and of the 122-amino-acid CadC polypeptide in Escherichia coli were identified by using the T7 RNA polymerase-promoter expression system. A truncated CadA polypeptide (402 amino acids) did not confer resistance in S. aureus but was expressed in E. coli under control of the T7 RNA polymerase-promoter. Removal of 678 nucleotides from the 5' end of the published sequence (which includes the cadA promoter) abolished resistance to cadmium, whereas a 146-nucleotide-shorter deletion was without effect. The cadC gene is needed in addition to cadA for full resistance to cadmium in S. aureus and Bacillus subtilis. cadC functions both in cis and in trans.
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PMID:A second gene in the Staphylococcus aureus cadA cadmium resistance determinant of plasmid pI258. 193 59


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