共查询到20条相似文献,搜索用时 359 毫秒
1.
Claude Terrière Gérard Giordano Bruce Haddock Edgard Azoulay 《Biochemical and biophysical research communications》1983,111(3):830-839
A membrane-bound pathway for the biosynthesis of ubiquinone 8 (UQ8) in has been identified from the analysis of the precursors accumulated by mutants blocked in the pathway. Ubiquinone 8 (UQ8) deficient mutant which accumulate 2 octaprenylphenol (2-OPP) allowed to show that two components are involved in the hydroxylating system of this compound: one membranous, is cytochrome and the second cytoplasmic, is an NADPH cytochrome reductase. 相似文献
2.
Prabhakara V. Choudary G.Ramananda Rao 《Biochemical and biophysical research communications》1982,108(3):1293-1299
The requirement of a suitable energy source during the induced synthesis of nitrate reductase in was investigated. The levels of nitrate reductase induced were shown to be energy-dependent, and to vary in response to the type of carbon source provided. Glycerol, fructose, ethanol, glucose, and sucrose served as efficient energy sources. Growth rate of the yeast and the induced level of nitrate reductase were dependent on the ratio of carbon to nitrogen in the induction medium, and ratio of 2 being optimal. Induction of nitrate reductase was inhibited by uncouplers, 2,4-dinitrophenol (DNP), dicumarol and carbonyl cyanide -trifluoromethoxy phenyl hydrazone (CCCP), and by cyanide and azide, indicating an absolute energy-dependency. The facilitation of induction of a high level of nitrate reductase by exogenously added ATP as sole source of energy confirmed the obligate requirement of ATP for the synthesis of nitrate reductase in . 相似文献
3.
Dipak K. Ghosh Debjani Dutta Timir B. Samanta Ajit K. Mishra 《Biochemical and biophysical research communications》1983,113(2):497-505
Microsomal preparations of TS oxidised benzo(a)pyrene very efficiently in the presence of NADPH and O2 and exhibits a pH optimum of 8.0–8.2. The hydroxylation is also effected in presence of NaI04. Hydroxylation was inhibited by metyrapone, SKF-525A, PCMB, imidazole, carbon monoxide and flavone but not by cyanide, azide and antimycin A indicating thereby the involvement of cytochrome P-450 in this reaction. Inhibition by cytochrome C is consistant with the participation of NADPH-cytochrome C reductase in this hydroxylation. Reduced microsomes and its solubilized preparation, when treated with carbon monoxide, showed absorption maxima at 453 and 449 respectively. Different classical inducers of cytochrome P-450 induce the benzo(a)pyrene hydroxylase activity to varying degree and as such suggests the existence of multiple forms of cytochrome P-450 in this fungus. 相似文献
4.
M. Erecińska 《Biochemical and biophysical research communications》1977,76(2):495-501
Three lysine residues of horse heart cytochrome were modified by reaction with methyl-4-mercaptobutyrimidate hydrochloride and the free SH group of the latter was covalently linked to p-azidophenacyl bromide yielding a photoaffinity-labeled cytochrome . The photoaffinity-labeled cytochrome was bound by irradiation into a covalent complex with cytochrome oxidase. 相似文献
5.
Evelyne Rouer Patrick Dansette Philippe Beaune Jean-Paul Leroux 《Biochemical and biophysical research communications》1980,95(1):41-46
The thermally-induced changes of a cytochrome P-450 dependent activity (ethoxycoumarin-O-deethylase) and of the fluorescence polarization of diphenylhexatriene were compared in microsomes from lean, and mice. In lean mice, biphasic plots were obtained with break points in the same range of temperature by both methods, whereas, in and mice, no discontinuities were observed. These results may be related to a modified fatty acid composition of microsomal membranes in mutant mice. They exemplify the influence of the lipid environment on the monooxygenase system as also shown by the modified binding constants of cytochrome P-450 towards type II substrates in mice. 相似文献
6.
Yuji Kamiya Akira Sakurai Nobutaka Takahashi 《Biochemical and biophysical research communications》1980,94(3):855-860
Rhodotorucine which induces mating tube formation of cells in is metabolized rapidly by cells. By use of labeled rhodotorucine , the degradation was found to be proteolytic. Two peptide fragments Tyr-Pro-Glu-Ile-Ser-Trp-Thr-Arg and Asn-Gly-Cys(S-farnesyl) were identified as the metabolites. Proteolysis of the pheromone mainly occurred on the cell surface. Culture filtrate of cells at log phase did not metabolize rhodotorucine . 相似文献
7.
R. Vila A. Llobell J.A. Bárcena A. Paneque 《Biochemical and biophysical research communications》1978,84(4):943-949
Treatment of a partially purified nitrate reductase preparation from the aerobic bacterium with a variety of oxidizing agents, such as glutathione, ferricyanide and illuminated flavins, results in inactivation of the enzyme. Independently of the mode of inactivation, incubation in the presence of dithioerythritol causes almost full recovery of nitrate reductase activity. Our data suggest that nitrate reductase might be regulated through an interconversion process between an oxidized inactive form and a reduced active one. 相似文献
8.
Shigenori Tanaka Takanori Nakamura Takashi Morita Sadaaki Iwanaga 《Biochemical and biophysical research communications》1982,105(2):717-723
Exposure of amebocytes to bacterial endotoxins (lipopolysaccharides, LPS) results in the activation of the coagulation system, which consists of several protein components. During the separation of these components, a potent anticoagulant, named tentatively anti-LPS factor, which inhibits the endotoxin-mediated coagulation reaction, was found in both amebocytes from the hemolymphs of and . The principle purified partially from amebocyte lysate had a molecular weight less than 10,000, as judged with the ordinary gelfiltration experiment. It inhibited specifically the activation of factor B, which has recently been characterized to be a coagulation factor highly sensitive to LPS, but it did not inhibit the activities of the active factor B and the active clotting enzyme separated from the lysate. The inhibitory activity of anti-LPS factor disappeared almost completely by the treatments with pronase-P and subtilisin, suggesting its polypeptide-like substance, but it resisted to a boiling treatment. A possible site of the anticoagulant action on the coagulation system was discussed. 相似文献
9.
OKY-1581 is an effective inhibitor of thromboxane synthesis and . The generation of thromboxane B2 (TxB2), prostaglandin E (PGE) and prostaglandin F (PGF) was measured following clotting and during platelet aggregation induced by collagen. The presence of OKY 1581 either or caused a reduction in TxB2 generation during clotting and platelet aggregation with a concomitant increase in PGE and PGF. The effect could be observed two hours after oral or subcutaneous administration of 5 to 100 mg per rabbit and lasted for 24 to 48 hours. The reduction in TxB2 was not accompanied by an inhibition of clotting or platelet aggregation. OKY-1581 appears to be a suitable agent for studying the role of TxB2 in atherosclerosis. 相似文献
10.
Evelyn A. Devine Mary C. Moran Peter J. Jederlinic Anthony J. Mazaitis Henry J. Vogel 《Biochemical and biophysical research communications》1975,67(4):1589-1593
The transducing phage λd, carrying a portion of the chromosome including , is derived from the heat-inducible, lysis-defective strain λy199, which has the and deletions. Cleavage of λy199 DNA by RI endonuclease, followed by agarose slab gel electrophoresis, results in bands corresponding to the known C, D, E, and F segments of λ, and a segment A′ (A plus B minus minus , the cleavage site between A and B being eliminated). Cleavage of λd DNA by RI yields the expected D, E, and F segments of λ and four other segments, termed 14-1 through 14-4, whose length is 17.5, 6.2, 3.0, and 2.0 kilobases, respectively, as determined by electron microscopy and corroborated by electrophoretic mobility. Heteroduplex analysis shows that the cluster is on the 14-1 segment. 相似文献
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12.
G. Sheir-Neiss R.V. Nardi M.A. Gealt N.R. Morris 《Biochemical and biophysical research communications》1976,69(2):285-290
[35S] labeled extracts of the fungus were copolymerized with purified porcine brain tubulin. The [35S] protein which copurified with porcine microtubules was found to be similar to [3H] chick tubulin when the two were coelectrophoresed on several polyacrylamide gel electrophoresis systems. These results strongly suggest the presence in of a tubulin-like protein. 相似文献
13.
Ronald M. Hamelik Mead M. McCabe 《Biochemical and biophysical research communications》1982,106(3):875-880
An inhibitor of , endodextranase was detected in proteins prepared from batch cultures of , strains representing serotypes through . Affinity chromatography of strain 6715-49 proteins, which apparently were free of endodextranase activity, yielded an active endodextranase and, in a separate peak, the endodextranase inhibitor. The presence of the inhibitor in culture fluids accounts for the absence of endodextranase activity in batch-grown cultures of , known to produce this enzyme. 相似文献
14.
Thermotropic properties of purified cytochrome and cytochrome have been studied by differential scanning calorimetry under various conditions. Both cytochromes exhibit a single endothermodenaturation peak in the differential scanning calorimetric thermogram. Thermodenaturation temperatures are ionic strength, pH, and redox state dependent. The ferrocytochromes are more stable toward thermodenaturation than the ferricytochromes. The enthalpy changes of thermodenaturation of ferro- and ferricytochrome are markedly dependent on the ionic strength of the solution. The effect of the ionic strength of solution on the enthalpy change of thermodenaturation of cytochrome is rather insignificant. The formation of a complex between cytochromes and at lower ionic strength causes a significant destabilization of the former and a slight stabilization of the latter. The destabilization of cytochrome upon mixing with cytochrome was also observed at high ionic strength, under which conditions no stable complex was detected by physical separation. This suggests formation of a transient complex between these two cytochromes. When cytochrome was complexed with phospholipids, no change in the thermodenaturation temperature was observed, but a great increase in the enthalpy change of thermodenaturation resulted. 相似文献
15.
Uterine stage embryos collected from the hamster (8-cell) and cow (morula, early blastocyst) were monitored for development (embryo culture) and (embryo transfer) following premature removal of the zona pellucida.Removal of the zona pellucida did not significantly affect development to the blastocyst stage of (1) 8-cell hamster embryos (zonae removed by a combined enzymic-mechanical procedure), (2) bovine morulae (zonae removed by mechanical means only) (3) early bovine blastocysts (zonae removed by the enzymic-mechanical technique).Zona-free hamster embryos formed significantly fewer viable fetuses than did zona-intact embryos. The lower incidence of fetal development observed following transfer of zona-free 8-cell hamster embryos may have resulted in part from the formation of chimeras by fusion of these embryos . Such fusion was observed to occur between zona-free embryos placed in close proximity. The proportion of pregnancies resulting from transfer of bovine blastocysts cultured from zona-free morulae was similar to that of zona-intact embryos.In this study we have demonstrated that (1) enzymic and mechanical procedures used to remove zonae pellucidae from uterine-stage hamster and bovine embryos do not adversely affect subsequent development of these embryos and and (2) zonae pellucidae are not required for normal development of these embryos. These findings have implications for microsurgery of mammalian embryos and for embryo transfer. 相似文献
16.
Tetsuo Sawai Laura J. Crane J.O. Lampen 《Biochemical and biophysical research communications》1973,53(2):523-530
The plasma membrane-bound penicillinase of has been purified. Amino acid analysis showed no significant differences in composition between the enzyme and exopenicillinase. Enzyme purified from cultures containing H333PO4 or [3H]-glycerol contained 33P or [3H]-glycerol activity and treatment with 8 M urea, 0.2% sodium dodecyl sulfate at 80° C did not remove the 3H-activity from the enzyme protein. Trypsin readily cleaved the glycerol-containing moiety from the enzyme protein, forming enzyme with molecular weight and heat stability like that of the exoenzyme. Phospholipase D and C also produced enzyme resembling the exo-form. 相似文献
17.
P. Bertrand M. Bruschi M. Denis J.P. Gayda F. Manca 《Biochemical and biophysical research communications》1982,106(3):756-760
Cytochrome c553 is a monohaemic c type cytochrome isolated from the sulfate reducing bacteria ,. Its midpoint potential value, determined by optical, EPR and polarographic studies is significantly lower than the midpoint potentials reported for other monohaemic cytochromes c (+ 10 mV instead of + 290 mV). In an attempt to study correlations between amino acid sequence, haem iron coordination and haem exposure in cytochromes c, cytochrome c553 is compared with mitochondrial and bacterial c type cytochromes. 相似文献
18.
J.A. Pérez-González A. Jiménez 《Biochemical and biophysical research communications》1984,125(3):895-901
The paromomycin producing organism is resistant to this antibiotic and contains a phosphotransferase which inactivates paromomycin. The gene encoding this enzyme has been inserted in the vector pIJ702 and then cloned in , selecting for paromomycin-resistance. Three plasmids have been isolated and one of them, pMJ1, contains a 2.2 kb insert with a single HindIII restriction site. Insertion of foreign DNA in this site blocks the expression of the phosphotransferase enzyme indicating that it is within the cloned gene. These findings provide a new dominant selective marker for cloning vectors with the versatility of insertional inactivation. 相似文献
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20.
Kazuo Yoshida Michio Hagiya Naohiko Yanagishima 《Biochemical and biophysical research communications》1976,71(4):1085-1094
The substance responsible for the sexual agglutinability was successfully solubilized by a newly established autoclaving method from the surface of mating type cells of and purified by DEAE cellulose chromatography, gel filtration, affinity chromatography and electrophoresis. The substance was found to consist of at least two different glycoprotein subunits. The molecular weight of the substance was estimated to be about 23,000 daltons by gel filtration. The substance was univalent in its biological activity and specifically masked the sexual agglutinability of the mating type α cells. The substance formed a complementary complex with the agglutination substance from α cells in vitro. 相似文献