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 reaction of cytidylic acid with O-delta-aminooxybuthylhydroxylamine H2NO(CH2)4ONH2 (delta-HA) was studied. The reaction occurs in agreement with the mechanism of the cytidine and hydroxylamine or O-methylhydroxylamine interaction and results in appearance of two compounds: 4-O-delta-aminooxybuthyloxyme of 6-O-delta-aminooxybuthoxyamino-5,6-dihydrouridine-5'-phosphate and 4-O-delta-aminooxybuthyloxyme of uridine-5'-phosphate. These products are produced in pure form by gel-chromatography and these structures are evidenced by UV- and PMR-spectroscopy and by reaction with acetone. The kinetics of correspondent reaction was studied by UV-spectroscopy.
Mol Biol (Mosk)
PMID:[Reaction of cytidylic acid with O-delta-aminooxybutylhydroxylamine]. 709 61

The dark-adapted form of bacteriorhodopsin in the purple membrane of Halobacterium halobium changes its absorption maximum from 560 to 600 nm if the pH is lowered to about 2 [Oesterhelt, D., & Stoeckenius, W. (1971) Nature (London), New Biol. 233, 149; Moore, T. A., Edgerton, M. E., Parr, G., Greenwood, C., & Perham, R. N. (1978) Biochem. J. 171, 469; Mowery, P. C., Lozier, R. H., Chae, Q., Tseng, T.-W., Taylor, M., & Stoeckenius, W. (1979) Biochemistry 18, 4100; Fischer, U., & Oesterhelt, D. (1979) Biophys. J. 28, 211; Muccio, D. D., & Cassim, J. Y. (1979) J. Mol. Biol. 135, 595]. We compared the pH dependence of the absorption spectra of acetylated membrane with that of unacetylated native membrane. The completely acetylated membrane showed a midpoint of pH 4.8 for the conversion to the acidic form; that of the native membrane was 3.4. On acetylation, the absorption maximum at neutral pH moved from 560 to 555 nm with about 20% decreases in extinction coefficients as compared with that of the native membrane, whereas the spectrum in acid was not affected. The chloride-dependent blue shift from the acidic form of the acetylated membrane was largely suppressed. The CD spectrum of the acetylated membrane was composed of two bands of an opposite sign with slightly decreased amplitudes. The chromophore of the acetylated membrane was sensitive to hydroxylamine, and the spectrum before bleaching was restored on addition of all-trans-retinal to the bleached membrane followed by dark incubation. Blue light irradiation accelerated the conversion to the acidic form in the native membrane but not in the acetylated membrane. Reductive ethylation did not affect the pH dependence of the absorption spectra.
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PMID:Absorption spectral properties of acetylated bacteriorhodopsin in purple membrane depending on pH. 712 52

The kinetics and reversibility of the suicide inactivation of rat liver cytochrome P-450 by chloramphenicol have been investigated with the use of a reconstituted monooxygenase system purified from liver microsomes of phenobarbital-treated rats. At a ratio of 1 unit of NADPH-cytochrome P-450 reductase per nanomole of cytochrome P-450 and a chloramphenicol concentration of 1 mM, the t1/2 for the inactivation of cytochrome P-450 is less than 2 min. The inactivated cytochrome regains some of its activity upon incubation at 25 degrees or 37 degrees, and experiments with [14C]chloramphenicol show that this partial reactivation is accompanied by the release of some of the 14C originally bound covalently to the cytochrome P-450. Previous work has shown that the 14C-labeled material spontaneously released from 14C-labeled cytochrome P-450 is in the form of oxalic acid, and that the latter is derived from a hydroxylamine-labile adduct of chloramphenicol and cytochrome P-450 [Biochem. Pharmacol. 30:875-881 (1981)]. In the present investigation the 14C-labeled material released by hydroxylamine was identified as the hydroxamic acid of oxalic acid. Trapping experiments with the amino acid cysteine suggest that the adduct, the spontaneous degradation of which appears to be involved in the reactivation of cytochrome P-450, contains an ester rather than a thioester linkage between cytochrome P-450 and a metabolite of chloramphenicol. However, this metabolite may not be identical with chloramphenicol oxamyl chloride, which was the active metabolite implicated in the formation of the 50% covalently bound material which was stable to hydroxylamine treatment.
Mol Pharmacol 1982 Jan
PMID:Further studies of the suicide inactivation of purified rat liver cytochrome P-450 by chloramphenicol. 713 55

Exposure of calf uterine estradiol-receptor complexes to diethylpyrocarbonate (ethoxyformic anhydride) at pH 6.3-6.5 results in a decrease in the ability of the receptor to bind to oligodeoxyribonucleotides. The inhibition of binding to oligodeoxypyrimidines is greater than the inhibition of binding to oligodeoxyguanylate. The inhibition by 6.6 mM diethylpyrocarbonate is complete within 10 min at 4 degrees C. Addition of equimolar quantities of histidine or imidazole prior to exposure to diethylpyrocarbonate prevents subsequent inhibition of oligodeoxyribonucleotide binding. In comparison to histidine, other amino acids tested were deficient in this ability. Diethylpyrocarbonate modification of the receptor causes complete loss of oligodeoxyribonucleotide binding activity at times when there is a loss of less than 20% of bound steroid. Pyridoxal 5'-phosphate treatment of receptor does not prevent subsequent modification by diethylpyrocarbonate, suggesting that the site of reaction is not an essential lysine of the DNA-binding domain. Treatment of the ethoxyformylated receptor with 0.45 M hydroxylamine results in recovery of 70% of the receptor's oligonucleotide-binding ability. The time course of the reaction of diethylpyrocarbonate with the estradiol receptor and the demonstration of hydroxylamine reversal of inhibition suggest that histidine is involved in the binding of estradiol receptor to oligodeoxyribonucleotides.
Mol Cell Endocrinol 1981 Jun
PMID:Diethylpyrocarbonate inhibition of estradiol receptor binding to oligonucleotides. 725 Apr 88

The interaction of a O-derivated analog of hydroxylamine-O-beta-diethylaminoethyl-hydroxylamine (OHA) with bacteriophage SD DNA in situ was studied. It was established that OHA modifies the cytidine of phage DNA up to 2% from the total cytidine quantity. The terminal ratio products of modification cytidine corresponds to the ration of modification products for completely denaturated DNA. The results obtained are interpreted in terms of locally denaturated regions spaced in the whole genome of SD bacteriophage.
Mol Biol (Mosk)
PMID:[Modification of the DNA of bacteriophage Sd in situ by O-beta-diethylaminoethylhydroxylamine]. 738 33

Despite previous reports [McLaughlin (1985) Mol. Biochem. Parasitol. 15, 189-201; Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Mazumder, Mukherjee, Ghosh, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] suggesting that the plasma-membrane Ca(2+)-ATPases of different trypanosomatids differ from the Ca2+ pumps present in mammalian cells, Trypanosoma cruzi plasma-membrane Ca(2+)-ATPase shares several characteristics with the Ca2+ pumps present in other systems. This enzyme could be partially purified from epimastigote plasma-membrane vesicles using calmodulin-agarose affinity chromatography. The activity of the partially purified enzyme was stimulated by T. cruzi or bovine brain calmodulin. In addition, the enzyme cross-reacted with antiserum and monoclonal antibody 5F10 raised against human red-blood-cell Ca(2+)-ATPase, has a molecular mass of 140 kDa and forms Ca(2+)-dependent hydroxylamine-sensitive phosphorylated intermediates. These results, together with its high sensitivity to vanadate, indicate that this enzyme belongs to the P-type class of ionic pumps.
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PMID:Characterization of the plasma-membrane calcium pump from Trypanosoma cruzi. 753

The highly acidic soluble organic matrix (SM) isolated from shells of the Antarctic scallop, Adamussium colbecki, was shown to consist of 1.5% carbohydrate by weight and 12.8% phosphate by weight. Total SM is composed of approximately 31% Asx, 29% Ser, and 18% Gly. Separation of the SM using RP-HPLC yielded a minimum of six protein fractions labeled RP-1 through RP-6 in order of elution off the column. The first fraction, RP-1, was found to be an effective inhibitor of calcium carbonate crystal nucleation in vitro suggesting a role for this protein in the regulation of shell mineralization. A less acidic fraction, RP-3, showed less inhibitory activity and dephosphorylation of RP-1 resulted in almost complete loss of inhibitory activity. Automated Edman degradation was used to sequence peptides generated by chemical cleavage of RP-1. Mild acid hydrolysis yielded peptides with sequences of N-S-G-D-D-D-D-G-G-OH, N-S-G-G-(S,G)-G-OH, and N-S-G-R-G-OH. Cleavage with hydroxylamine yielded peptides of N-D-D-D-D-D-D-D-D-OH, N-L-Y-Y-OH, and N-A-V-G-E-S-D-OH. These data suggest biochemical similarities between this SM and other SM proteins isolated from both calcium carbonate and calcium phosphate biominerals, and presents evidence of a primary domain structure similar to that described for oyster SM and phosphophoryn isolated from rat dentin.
Comp Biochem Physiol B Biochem Mol Biol 1995 Jun
PMID:Characterization of organic matrix macromolecules from the shells of the Antarctic scallop, Adamussium colbecki. 759 87

Activation of C3 results in the generation of metastable C3b, which has been shown to preferentially react with the hydroxyl groups of carbohydrates and with specific serine and threonine residues in proteins. In this study we have examined the reactivity of metastable C3b with the third type of hydroxyl group present in proteins, tyrosine (Tyr). The results demonstrated that Tyr reacts with the thioester of metastable C3b and that this reactivity was 11-fold better than that of threonine, 47-fold better than serine and 50-fold better than the reactivity of carbohydrates. Model peptides containing Tyr showed even higher reactivity than free Tyr, demonstrating that incorporation into peptide structures does not block C3b attachment. The site of attachment was found to be in the alpha'-chain of C3b and the bond was hydroxylamine sensitive, indicating an ester linkage. The stability of the C3b-Tyr complex was measured under physiological conditions (pH 7.4, 37 degrees C) and compared to the stability of other C3b complexes. C3b-Tyr decayed 50% in 19 hr at 37 degrees C, but C3b bound to a Tyr-containing peptide was more stable, exhibiting a t1/2 of 53 hr. The ester linked complexes C3b-IgG and C3b-glycerol were less stable each exhibiting a t1/2 of approximately 8 hr. As yet, only two specific C3b attachment sites on proteins have been identified, Ser1217 in C4b and Thr144 in IgG1. The present evidence demonstrates that Tyr residues are highly reactive and that the C3b-Tyr linkage is stable. The findings suggest that complexes involving tyrosine residues as the site of attachment will also be found.
Mol Immunol 1995 Jul
PMID:Tyrosine is a potential site for covalent attachment of activated complement component C3. 765 97

The ability of a ras protein to associate with proteins present in rat brain cytosol in vitro was investigated using chemical cross-linking agents and the 125I-labelled v-H-ras protein. Two iodinated protein complexes with apparent molecular weights of 40 and 85 kDa were observed when a mixture of rat brain cytosol and [125I] ras was treated with the cross-linking agent disuccinimidyl suberate and subjected to SDS-PAGE. Formation of the [125I] Formation of the[125I] 85 kDa complex was enhanced by a high concentration of EDTA while generation of the 40 kDa species was abolished by this treatment. Formation of the [125I] 85 kDa complex was inhibited by unlabelled ras protein, GTP, GTP gamma S, and GDP but not by ATP gamma S and GMP. Chromatography of the cross-linked brain cytosol[125I] ras mixture on DEAE cellulose partially resolved the [125I] 85 kDa complex from the [125I] ras protein. The [125I] 85 kDa complex (formed using ethyleneglycolbis (succinimidylsuccinate) as the cross-linking agent) could be immunoprecipitated using a rabbit anti-ras polyclonal antibody. Treatment of the immunoprecipitate with hydroxylamine to cleave the cross-link yielded [125]I-labelled ras. A substantial enrichment of the proportion of the [125I] 85 kDa complex in the cross-linked extract was achieved by preparative SDS-PAGE. It is concluded that the in vitro chemical cross-linking approach employed here has detected two ras binding proteins in rat brain cytosol: a 65 kDa heat-sensitive and a 20 kDa heat-stable protein.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Cell Biochem 1995 Apr 26
PMID:Detection of a 65 kDa ras binding protein in rat and sheep brain cytosol using a chemical cross linking agent. 767 31

A plasmid encoding ribonuclease P RNA of Escherichia coli (M1 RNA) was mutagenized with hydroxylamine in vitro and defective rnpB genes were identified by screening in an in vivo suppression assay. Defective rnpB sequences were mutagenized with a second round of hydroxylamine to restore activity. We report here that conversion of the C32.G48 base-pair of RNase P RNA to either C.A or U.G restored activity to defective rnpB genes bearing a variety of spatially distinct primary mutations. Disruption of this base-pair in an otherwise wild-type rnpB sequence increased the growth rate of the indicator strain E. coli FS101, consistent with the opening of C32.G48 during in vivo assembly of or catalysis by RNase P.
J Mol Biol 1993 Mar 05
PMID:Suppression of loss-of-function mutations in Escherichia coli ribonuclease P RNA (M1 RNA) by a specific base-pair disruption. 768 Jul 23


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