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Query: UNIPROT:P06889 (
Mol
)
630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The efficiency of Escherichia coli nucleic acids samples: covalently closed circular DNA, linear chromosomal DNA, total RNA degradation mediated by the action of high oxygen pressure; hydrochloric hydroxylamine in alkaline conditions in the presence of cooper ions and in analogous conditions without cooper ions was studied. The nativity of nucleic acids was determined by means of fluorometric analysis of nucleic acids/ethidium bromide complexes. Experiments revealed, that the destructive effect of active oxygen species decreased in the following order: NH2OH.
HCl
in alkaline conditions in the presence of copper ions-NH2.
HCl
in alkaline conditions--high pressure of pure oxygen. The stability of nucleic acids decreased in the following order: covalently closed circular DNA-linear DNA-RNA.
Mol
Biol (Mosk)
PMID:[Degradation of nucleic acids during generation of superoxide-anion in the presence of copper ions]. 245 81
The possibility of use of 7-amino-actinomycin D (7aAMD)--fluorescent analog of actinomycin D--as a specific dye for DNA staining in the suspended cells was studied by means of laser flow-cytometry. The optimal conditions for staining were obtained: 7aAMD concentration 10(-5) M, pH 7, staining time 20 min, 37 degrees C, ionic strength 0.15 M Na+. In this case the fluorescent signal is proportional to the DNA amount and coefficient of variation is about 0.03. The influence of the stepwise extraction of the proteins from chromatin also was studied. In the course of the salt deproteinization the fluorescence intensity gradually rose thus showing the increase of the binding sides-number. The deproteinization of cells nuclei by 0.1
HCl
increased the number of binding sites 2.5 times more. It was shown that the incubation of cells with RNAse at elevated ionic strength (0.3-0.7 M NaCl) leads to an additional increase of the cell fluorescence and produces no effect at low and normal ionic strength. The deproteinizing effect of RNAse and its possible mechanism is discussed.
Mol
Biol (Mosk)
PMID:[Effect of deproteinization on the in situ chromatin staining with 7-aminoactinomycin D]. 246 Jul 38
After cryosubstitution and Epon embedding, or after Nanoplast embedding and very thin sectioning, the chromatin of ejaculated or diluted boar spermatozoa appears to be formed of DNA fibers embedded in a quite homogeneous matrix. After sodium dodecyl sulfate (SDS) treatment, and to a lesser extent after freeze-thawing, the DNA fibers are present mostly between cords, probably proteinaceous in nature. The quantity of free sulfhydryl (SH) groups, as calculated from staining by DACM and flow fluorometry, is increased in thawed or SDS-treated cells. The quantity of NH2 groups, calculated from electron microscopy image analysis of alcoholic phosphotungstic acid-stained cells, is decreased in thawed nuclei. The DNA is more accessible to the fluorochrome ethidium bromide after freeze-thawing, and its sensitivity to
HCl
hydrolysis is modified, during the Feulgen-like staining procedure using acriflavine. The X-ray energy dispersive analysis of cryosections of nuclei indicates that the slight separation of DNA and nucleoproteins in freeze-thawed spermatozoa could result from a dramatic modification of the nuclear ionic environment during thawing.
Mol
Reprod Dev 1989
PMID:Nucleus of the boar spermatozoon: structure and modifications in frozen, frozen-thawed, or sodium dodecyl sulfate-treated cells. 248 17
Urine with trace amounts of different proteins from healthy people or B-lymphoma patients was concentrated and separated simultaneously by counterflow isotachophoresis on cellulose acetate membranes (CAM). The protein zones were blotted onto nitrocellulose membrane (NCM) by direct contact of CAM and NCM. NCM-blots were exposed to second isotachophoresis with the leading electrolyte 0.06 M Tris-
HCl
and the terminating one, 0.012 M Tris-beta-alanine. Under these conditions the moving boundary formed by Cl-/beta-alanine- migrated towards the anode with decreasing velocity. At a certain point the rate of migration of the moving boundary became completely compensated by the electroendosmotic counterflow. In this steady state position the boundary stopped on the NCM support, while the electroendosmotic rate in the area before the boundary was much higher than the rate of the opposite migration of any protein to the anode. Under these conditions electroendosmosis served as a "conveyer belt" which transferred consecutively the immunoreagents, antibodies, immunoconjugates, or antiperoxidase-peroxidase system through the protein blots "printed" on NCM. The immunoblots obtained in this way were developed by the substrate for the immunoenzyme complex used in the experiment. The technique could be used to characterize light chains present in the urine of normal donors and monoclonal light chains in the urine of patients with B-cell malignancies.
Mol
Immunol 1989 Jan
PMID:Performance of multistep immunochemical reactions by counterflow isotachophoresis on nitrocellulose membranes--I. Immunoblotting. 249 35
In low ionic strength buffer (5 mM Tris.
HCl
), the binding of [3H] nitrendipine to dihydropyridine calcium antagonist binding sites of mouse forebrain membranes is increased by both Na+ and Ca2+. Radiation inactivation was used to determine the target size of [3H]nitrendipine binding sites in 5 mM Tris.
HCl
buffer, in the presence and absence of these cations. After irradiation, [3H] nitrendipine binding in buffer with or without Na+ was diminished, due to a loss of binding sites and also to an increase in Kd. After accounting for radiation effects on the dissociation constant, the target size for the nitrendipine binding site in buffer was 160-170 kDa and was 170-180 kDa in the presence of sodium. In the presence of calcium ions, [3H]nitrendipine binding showed no radiation effects on Kd and yielded a target size of 150-170 kDa. These findings suggest, as in the case of opioid receptors, the presence of high molecular weight membrane components that modulate cation-induced alterations in radioligand binding to dihydropyridine binding sites.
Mol
Pharmacol 1989 Aug
PMID:Radiation inactivation reveals discrete cation binding sites that modulate dihydropyridine binding sites. 254 88
Rat liver lysosomes have been used to characterize further the effects of ATP on lysosomal stability during incubation at 37 degrees C at hypo-osmolarity. As previously reported, when the osmotically-supporting solute is the salt of a strong base (K+), ATP protects against lysis during incubation. However, if the osmotically-supporting solute is the salt of a weak base, e.g. Tris
HCl
or NH4Cl, ATP actually promotes lysis during incubation. Thus, ATP can exert destabilizing as well as protective effects on lysosomes. The destabilizing effect is eliminated by protonophores. The protective effect in the presence of potassium salts is not eliminated by protonophores. Moreover, when incubation is in the presence of a salt of a weak base, protonophores actually cause an ATP-dependent protective effect to be established. The destabilizing effect occurs at 37 degrees C, but not at 0 degrees C. The Mg++-dependence of the destabilizing effect was found to be similar to that found earlier for the ATP-dependent protective effect, insofar as only 1 mM MgCl2 in the presence of 1mM EDTA is sufficient for nearly maximal stimulation of both effects. The destabilizing effect may result from a H+ ion gradient across the lysosomal membrane which is maintained by the lysosomal ATP-dependent proton pump. The protective effect, on the other hand, does not depend on such a gradient being maintained; on the contrary, protonophores appear to act as enablers of the protective effect. The question that remains to be answered is: does the protective effect derive in some way from the same ATP-driven mechanism which constitutes the proton pump? Some possible answers to this question are considered.
Mol
Cell Biochem 1989 Oct 31
PMID:Is the ATP-dependent protection of lysosomes against osmotic lysis a function of the lysosomal proton pump. 258 96
Twenty chemicals were tested for their ability to induce sister chromatid exchanges (SCEs) and chromosomal aberrations (ABs) in cultured Chinese hamster ovary cells (CHO). These chemicals were tested with and without an added metabolic activation system (rat liver S9 fraction). Four chemicals were negative in both assays, 1 induced ABs only, and 15 were positive for SCEs; 6 of these 15 also induced ABs. The effect of cell harvest time on the ability to detect the induction of chromosomal aberrations was examined for six chemicals. Five of these had caused at least one of the following: cell cycle delay, aberrations observed in first division metaphase cells in the SCE assay, or a weak response in the standard AB assay (10-12-hr growth period). Three chemicals, chlorinated trisodium phosphate, 1,2-dibromo-3-chloropropane, and tetrakis(hydroxymethyl)phosphonium chloride, were positive using both the standard and extended harvest times. N-Nitrosodimethylamine and diphenhydramine
HCl
were only positive using an extended harvest time, and malonaldehyde was negative using both standard and extended harvest times.
Environ
Mol
Mutagen 1989
PMID:Chromosome aberration and sister chromatid exchange tests in Chinese hamster ovary cells in vitro: II. Results with 20 chemicals. 264 6
The specific DNA-binding protein FIS (factor for inversion stimulation), which stimulates site-specific DNA inversion by interaction with an enhancer sequence, was purified from an Escherichia coli strain overproducing the protein. FIS was crystallized at room temperature by microdialysis against 1.2 to 1.5 M-sodium/potassium phosphate containing 10 mM-Tris.
HCl
, 0.5 to 1 M-NaCl and 1 mM-NaN3 at pH 8.0 to 8.2. The crystals are stout prisms and suitable for X-ray diffraction study beyond 2.5 A resolution. They belong to the orthorhombic space group P2(1)2(1)2(1). The unit cell has dimensions a = 47.57(4) A, b = 51.13(4) A, c = 79.83(6) A and contains one FIS dimer in the asymmetric unit.
J
Mol
Biol 1989 Jul 05
PMID:Crystallization of the DNA-binding Escherichia coli protein FIS. 267 86
Normal bovine erythrocytes have negligible ability to transport adenosine and related nucleosides across their cell membrane. However, infection with the intraerythrocytic parasite Babesia bovis was found to induce a nucleoside permeation site into the host cell membrane. Transport experiments over periods of up to 30 s determined that the transport rate of 1 microM adenosine into the infected cell was 1.72 +/- 1.2 pmol incorporated (microliter cell water)-1s-1, a rate three times higher than for normal human erythrocytes. Incorporation studies over 6 h with labelled adenosine indicated that the purine moiety was incorporated into parasite nucleic acids. The mammalian nucleoside transport inhibitors, nitrobenzylthioinosine (NBMPR), nitrobenzylthioguanosine (NBTGR), dilazep and dipyridamole inhibited the induced nucleoside transport mechanism in the Babesia-infected erythrocytes, though at higher concentrations than those required to inhibit normal human erythrocyte transport. An ID50 value for NBMPR of 0.36 microM was determined. Phloretin and 5'-p-fluorosulphonyl benzoyl adenosine-
HCl
(5FSBA) were also shown to be inhibitory, with ID50 values of 0.11 and 0.18 microM, respectively, whilst phlorizin and verapamil at 1 microM had no effect. Binding studies with [3H]NBMPR indicated that high-affinity NBMPR binding sites could not be detected in either normal or B. bovis infected bovine erythrocytes. The results indicate that the induced nucleoside permeation site(s) in B. bovis infected erythrocytes has characteristics different from either human erythrocytes or erythrocytes infected with the malarial parasites Plasmodium falciparum or Plasmodium yoelii.
Mol
Biochem Parasitol 1989 Jul
PMID:Induction of nucleoside transport sites into the host cell membrane of Babesia bovis infected erythrocytes. 274 45
Incubation of rat ovarian plasma membranes with [gamma-32P]guanosine 5'-triphosphate (GTP) in the presence of an adenosine triphosphate (ATP)-trapping system results in the labeling of a single protein, Mr 33,000 +/- 3000 designated 'a' (Amir-Zaltsman, Y., Ezra, E., Walker, M., Lindner, H. R. and Salomon, Y. (1980) FEBS Lett. 122, 166-170). Based on competition with other nucleotides it is concluded that protein 'a' is preferentially phosphorylated by [gamma-32P]GTP (Km = 0.28 microM). Phosphorylation of protein 'a' does not occur at pH less than 5 and progressively increases to plateau levels at pH 7-9. Phosphorylation of protein 'a' is absolutely dependent on the presence of divalent cations 1 mM Mg2+, Ca2+, or Cd2+. At higher concentrations, 5-20 mM, Mg2+ or in the presence of 1 mM Mn2+ ions other proteins are also phosphorylated. While vanadate ions selectively prevent the labeling of protein 'a', molybdate ions were found to inhibit phosphorylation of all the membrane proteins including protein 'a'. In contrast to molybdate ions, vanadate ions were found to accelerate the dephosphorylation of phosphoprotein 'a'. We suggest that phosphoprotein 'a' is a high energy protein intermediate in which the phosphate is present as a phosphoramidate for the following reasons: (i) Guanosine diphosphate (GDP) but not guanosine 5'-O-(2-thiodiphosphate) selectively accelerated the dephosphorylation of phosphoprotein 'a' but only in the presence of Mg2+ ions. (ii) The phosphoprotein intermediate is hydrolyzed in the presence of hydroxylamine. (iii) Phosphoprotein 'a' is labile in the presence of 1 N
HCl
but stable in 1 N NaOH at 37 degrees C. (iv) Phosphoprotein 'a' is heat labile. Phosphoprotein 'a' is readily digested by several proteolytic enzymes and a single cleavage peptide is generated upon treatment with Staphylococcus aureus V8 protease. The properties of protein 'a' were compared and found different from another phosphoprotein Mr 90,000 +/- 1000, designated 'b' that was selected arbitrarily. We propose that protein 'a' is a GTP requiring enzyme intermediate, of yet unidentified function.
Mol
Cell Endocrinol 1989 May
PMID:Phosphorylation of proteins in rat ovarian plasma membranes by [gamma-32P]GTP: evidence for the formation of a high energy phosphoprotein. 275 26
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