Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The goat spermatozoa membranes isolated after treatment with octa (ethylene glycol) mono n-dodecyl ether (C12E8) followed by discontinuous sucrose density gradient centrifugation have been found to contain an ATPase that is stimulated by externally added Ca2+ only. The membrane fraction has also found to contain Mg(2+)-dependent Ca(2+)-ATPase activity, however the former activity is about 2 fold higher than the latter. The molecular weight of the enzyme is found to be about 97,000 on SDS-polyacrylamide gel. The optimum concentration of Ca2+ required for maximum activity is 3 mM for both Mg(2+)-dependent and Mg(2+)-independent Ca(2+)-ATPase. Histidine and imidazole buffers are found to be the most suitable for dependent and independent enzyme activities respectively. ATP with an optimum concentration of 4 mM is observed to be the best substrate than any other nucleotides. The inhibitors like trifluoperazine and vanadate and group specific probes e.g. DTNB and TNBS inhibit these two enzymes but at different rates. Ca(2+)-uptake study shows that the uptake in the presence of Ca2+ and ATP is higher than in the presence of Mg2+, Ca2+ and ATP. The findings lead us to believe that the Mg(2+)-independent Ca(2+)-ATPase has some role in Ca2+ transport like Mg(2+)-dependent enzyme.
Mol Cell Biochem 1991 May 15
PMID:Biochemical characterization of a calcium ion stimulated-ATPase from goat spermatozoa. 183 Jan 26

Halothane, an anesthetic with marked depressant effects on the circulation, was studied for its ability to inhibit inositol phosphate and Ca2+ signaling evoked by the vasoactive hormone arginine vasopressin (AVP) and Ca2+ responses elicited by platelet-derived growth factor and by thapsigargin in cultured A7r5 vascular smooth muscle cells. Changes in apparent [Ca2+]i were measured using the indicator indo-1 and flow cytometry, whereas inositol phosphate levels were determined using myo-[3H]inositol and column chromatography. Preincubation with clinically relevant concentrations of halothane resulted in dose-dependent depression of [Ca2+]i responses evoked on stimulation with AVP. Halothane (2.0%) inhibited the increases in [Ca2+]i by 34-45%. In cells incubated in Ca(2+)-free medium plus 0.5 mM ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, the halothane effect was more marked, with 1.5% halothane inhibiting the responses by approximately 53-61%. However, when Ca2+ influx was stimulated by addition of 5 mM Ca2+ in the continued presence of the agonist, the [Ca2+]i response was inhibited by only 15%, suggesting that release of Ca2+ rather than Ca2+ influx is more sensitive to inhibition by the anesthetic. The effects of halothane on Ca2+ homeostasis are not explained solely by anesthetic-induced depletion of Ca2+ from intracellular stores, because the anesthetic inhibited increases in [Ca2+]i elicited by thapsigargin in cells suspended in Ca(2+)-free medium by only 31%. Halothane inhibited inositol phosphate formation elicited by AVP, suggesting an additional means by which the anesthetic may alter agonist-induced Ca2+ responses. The current results also demonstrate that halothane actions are not specific solely to responses evoked by AVP, which acts via a guanine nucleotide-binding protein-linked signaling pathway, but include responses stimulated by platelet-derived growth factor, an agonist that elevates [Ca2+]i via receptor-latent tyrosine kinase activity. The current results demonstrate that, in vascular smooth muscle cells, halothane alters Ca2+ homeostasis, an action that may underlie the in vivo vasodilator effects of the anesthetic.
Mol Pharmacol 1991 Dec
PMID:Halothane inhibits agonist-induced inositol phosphate and Ca2+ signaling in A7r5 cultured vascular smooth muscle cells. 183 33

The highly purified preparations of Bollum's terminal transferase from calf thymus were shown to catalyze, along with the common reaction of nucleotide addition to the 3'-terminus of an oligonucleotide primer, a "non-common" reaction between dNTP or rNTP on one hand, and various alcohols on the other hand. This reaction was carried out with ethylene glycol, glycerol, ethanol and methanol to produce substances containing one molecule of nucleotide, one molecule of alcohol and non-organic pyrophosphate. The reaction conditions are cacodylate buffer, pH 7, 2, in the presence of Mg2+ or Co2+ ions. The structure was determined for the product of the reaction between glycerol and dATP, which appeared to be 2,3-dihydroxypropyl-ether of 2'-deoxyadenosine-5'-monophosphate.
Mol Biol (Mosk)
PMID:[A new reaction catalyzed by Bollum's terminal deoxyribonucleotidyltransferase]. 189 36

Twenty-seven chemicals were tested for their mutagenic potential in the L5178Y tk+/tk- mouse lymphoma cell forward mutation assay using procedures based upon those described by McGregor et al. (McGregor DB, Martin R, Cattanach P, Edwards I, McBride D, Caspary WJ (1987): Environ Mol Mutagen 9:143-160). Cultures were exposed to the chemicals for 4 hr, then cultured for 2 days before plating in soft agar with or without trifluorothymidine (TFT), 3 micrograms/ml. The chemicals were tested at least twice. Statistically significant responses were obtained with acid orange 10, aniline, benzaldehyde, o-chloroaniline, chlorodibromomethane, cytembena, 1,2-dibromo-4-(1,2-dibromomethyl) cyclohexane, dieldrin, lithocholic acid, oxytetracycline, phenazopyridine HCl, 1-phenyl-3-methyl-5-pyrazolone, sodium diethyldithiocarbamate, solvent yellow 14, tetraethylthiuram disulfide (disulfiram), 2,4-toluene diisocyanate, and 2,6-toluene diisocyanate. Apart from phenazopyridine HCl, acid orange 10, and solvent yellow 14, rat liver S9 mix was not a requirement for the mutagenic activity of these compounds. Chemical not identified as mutagens were N-4-acetylaminofluorene, chlorpheniramine maleate, chloropropamide, 1,4-dioxane, endrin, ethylene glycol, iron dextran, methapyrilene, sodium(2-ethylhexyl)alcohol
Environ Mol Mutagen 1991
PMID:Responses of the L5178Y mouse Lymphoma cell forward mutation assay. V: 27 coded chemicals. 190 15

This study evaluates the role of intracellular levels of Ca2+ [Ca2+]i in cyclic GMP formation mediated by muscarinic and histamine receptors in the mouse neuroblastoma clone N1E-115. Muscarinic agonists activated the turnover of phosphoinositides with a relative maximal response similar to that observed previously for cyclic GMP formation. Carbamylcholine induced a transient increase in inositol trisphosphate with a time course similar to that of cyclic GMP formation. In cells loaded with the fluorescent Ca2+ probe fura-2/acetoxymethyl ester, carbamylcholine as well as histamine induced a rapid and transient rise in [Ca2+]i. The time course of the changes in [Ca2+]i induced by agonists as well as by ionomycin closely paralleled that of cyclic GMP formation. Chelation of [Ca2+]i by loading of N1E-115 cells with quin 2/acetoxymethyl ester inhibited cyclic GMP formation induced by agonists in a dose-dependent manner. When cyclic GMP formation induced by agonists was assayed after the cells were exposed to 3 mM ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) for 2 min, the formation of cyclic GMP was not inhibited significantly; however, it was completely abolished after 30-min exposure to EGTA. Treatment of cells with phospholipase A2 had no effect on resting [Ca2+]i and only slightly increased cyclic GMP formation, in spite of the induction of a marked release of [3H]arachidonate. Moreover, the formation of cyclic GMP induced by ionomycin was inhibited by the addition of phospholipase A2. Melittin contaminated with phospholipase A2 activity induced a rapid and sustained increase in cyclic GMP formation, as well as unesterified [3H]arachidonate release. However, after inactivation of the phospholipase A2 activity of melittin, its ability to stimulate cyclic GMP formation was enhanced. Our data indicate that receptor agonists stimulate cyclic GMP formation in N1E-115 cells by activating the formation of inositol trisphosphate, which is followed by the release of Ca2+ from intracellular stores. The evidence obtained does not support a major role for arachidonate release in receptor-mediated activation of guanylate cyclase. Conversely, it is consistent with an inhibitory role for arachidonic acid or its metabolites in this process.
Mol Pharmacol 1990 Jun
PMID:Role of intracellular Ca2+ mobilization in muscarinic and histamine receptor-mediated activation of guanylate cyclase in N1E-115 neuroblastoma cells: assessment of the arachidonic acid release hypothesis. 197 74

The patch-clamp method has been used to determine the actions of three newly synthesized cardiac drugs on a calcium-dependent potassium channel, K(Ca), in CA1 hippocampal neurons. Activation of a 65-pS channel was evident in excised inside-out patches with the internal side of the membrane exposed to Ca2+ (0.2 mM); cessation of channel activity was immediate upon perfusion with ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid-containing solution. In the presence of low concentrations (0.1-10 microM) of the drugs UK-68798, KC-8857 (tedisamil), or WY-48986 (risotilide), channel openings evinced rapid flickering behavior from open to nonconducting levels; current amplitude was not affected by the drugs. The actions of the drugs were consistent with a voltage-independent block of open K(Ca) channels. In addition, the three drugs, at concentrations similar to those applied to inside-out patches, also blocked K(Ca) when they were applied to the bath solution for outside-out patches. The potencies for channel block of the drugs acting either externally or internally were in the order UK-68798 greater than tedisamil greater than risotilide, with UK-68798 reducing the mean open time of K(Ca) by one-half at a concentration near 0.4 microM.
Mol Pharmacol 1991 Apr
PMID:Actions of cardiac drugs on a calcium-dependent potassium channel in hippocampal neurons. 201 53

We report the low temperature carbon monoxide recombination kinetics after photolysis and the temperature dependence of the visible absorption spectra of the isolated alpha SH-CO and beta SH-CO subunits from human hemoglobin A in ethylene glycol/water and in glycerol/water mixtures. Kinetic measurements on sperm whale (Physeter catodon) myoglobin and previously published optical spectroscopy data on the latter protein and on human hemoglobin A, in both solvents, (Cordone, L., A. Cupane, M. Leone, E. Vitrano, and D. Bulone. 1988. J. Mol. Biol. 199:312-218) are taken as reference. Low temperature flash photolysis data are analyzed within the multiple substates model proposed by Frauenfelder and co-workers (Austin, R. H., K. W. Beeson, L. Eisenstein, H. Frauenfelder, and I. C. Gunsalus. 1975. Biochemistry. 14:5355-5373). Within this model a distribution of activation enthalpies for ligand binding accounts for the structural heterogeneity of the protein, while the preexponential factor, containing also the entropic contribution to the free energy of the process, is considered to be constant for all conformational substates. Optical spectra are deconvoluted in gaussian components and the temperature dependence of the moments of the resulting bands is analyzed, within the harmonic Frank-Condon approximation, to obtain information on the stereodynamic properties of the heme pocket. The kinetic and spectral parameters thus obtained are found to be protein dependent also with respect to their sensitivity to changes in the composition of the external medium. A close correlation between the kinetic and spectral features is observed for the proteins examined under all experimental conditions studied. The results reported are discussed in terms of differences in the heme pocket structure and in the conformational heterogeneity among the various proteins, as related to their different capability to accommodate constraints imposed by the external medium.
 ...
PMID:Protein dynamics. Comparative investigation on heme-proteins with different physiological roles. 204 28

Multifunctional acrylates are being used increasingly as replacements for solvents, and occupational and general population exposure to this structural class is expanding. Four multifunctional acrylates and acrylic acid were tested for mutagenicity in the Salmonella typhimurium and mouse lymphoma L5178Y TK+/-assays. In the Salmonella assay, two of the compounds (trimethylolpropane triacrylate and trimethylolpropane trimethacrylate) showed weakly positive results with a single tester strain (TA1535) in the presence of hamster liver S9; the other three compounds were negative. All five compounds were negative in the Salmonella assay without S9 activation. In the mouse lymphoma assay, two of the compounds (acrylic acid and ethylene glycol diacrylate) were positive in both the presence and the absence of S9, one compound was positive only in the presence of S9 (ethylene glycol dimethacrylate), and one compound was positive only in the absence of S9 (trimethylolpropane triacrylate).
Environ Mol Mutagen 1991
PMID:Genotoxicity of multifunctional acrylates in the Salmonella/mammalian-microsome assay and mouse lymphoma TK+/-assay. 205 Jan 34

We tested whether recombinant human superoxide dismutase conjugated to polyethylene glycol (PEG-SOD) to prolong its plasma retention time could limit myocardial infarct size in an ischemia-reperfusion model in the rabbit. One group of animals received 1000 units/kg of PEG-SOD as an intravenous bolus 15 min before coronary occlusion. A second group received saline only and served as controls. Under pentobarbital anesthesia, a left coronary branch was occluded for 30 min and then reperfused. The surgical wounds were repaired and the animals were allowed to recover. Seventy-two hours after the coronary occlusion, the heart was excised and the size of the area at risk (ischemic vascular bed) was assessed with fluorescent particles and the infarct size was determined by histology (Hematoxylin-eosin, Azan stain). Infarct size as a percentage of the area at risk was similar between the groups, 46.5 + 2.7 in the PEG-SOD group (n = 8) and 48.9 + 3.1 in the control group (n = 8). There were no significant differences between the groups indicating that PEG-SOD did not limit infarct size in this model.
J Mol Cell Cardiol 1991 Feb
PMID:Superoxide dismutase conjugated to polyethylene glycol fails to limit myocardial infarct size after 30 min ischemia followed by 72 h of reperfusion in the rabbit. 206 22

We report here an efficient and highly reproducible delivery system, using an improved biolistic transformation device, that facilitates transient expression of beta-glucuronidase (GUS) in chloroplasts of cultured tobacco suspension cells. Cultured tobacco cells collected on filter papers were bombarded with tungsten particles coated with pUC118 or pBI101.3 (negative controls), pBI505 (positive nuclear control) or a chloroplast expression vector (pHD203-GUS), and were assayed for GUS activity. No GUS activity was detected in cells bombarded with pUC118 or pBI101.3. Cells bombarded with pBI505 showed high levels of expression with blue color being distributed evenly throughout the whole cytosol of the transformants. pHD203-GUS was expressed exclusively in chloroplasts. We base this conclusion on: i) the procaryotic nature of the promoter used in the chloroplast expression vector; ii) delayed GUS staining; iii) localization of blue color within subcellular compartments corresponding to plastids in both shape and size; and iv) confirmation of organelle-specific expression of pHD203-GUS using PEG-mediated protoplast transformation. Chloroplast transformation efficiencies increased dramatically (about 200-fold) using an improved helium-driven biolistic device, as compared to the more commonly used gun powder charge-driven device. Using GUS as a reporter gene and the improved biolistic device, optimal bombardment conditions were established, consistently producing several hundred transient chloroplast transformants per Petri plate. Chloroplast transformation efficiency was found to be increased further (20-fold) with supplemental osmoticum (0.55 M sorbitol and 0.55 M mannitol) in the bombardment and incubation medium. This system provides a highly effective mechanism for introducing and expressing plasmid DNA within higher-plant chloroplasts, and the fact that GUS functions as an effective marker gene now makes many genetic studies possible which were not possible before.
Plant Mol Biol 1990 Dec
PMID:Optimization of delivery of foreign DNA into higher-plant chloroplasts. 210 74


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