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101.
102.
103.
Liposomes composed of soybean phosphatidylcholine were peroxidized using the reagent sodium hypochlorite or the myeloperoxidase-hydrogen peroxide-Cl- system. Linoleic acid hydroperoxide previously prepared from linoleic acid by means of lipoxidase was incorporated into liposomes. The yield of thiobarbituric acid reactive substances (TBARS) continuously increased with higher amounts of hydroperoxide groups after the initiation of lipid peroxidation by hypochlorous acid producing systems. The accumulation of TBARS was inhibited by scavengers of free radicals such as butylated hydroxytoluene and by the scavengers of hypochlorous acid, taurine and methionine. Lipid peroxidation was also prevented by sodium azide or chloride free medium in the myeloperoxidase-hydrogen peroxide-Cl- system. Here we show for the first time that the reaction of hypochlorous acid with a biologically relevant hydroperoxide yields free radicals able to cause further oxidation of lipid molecules. 相似文献
104.
The kinetic behaviour of the ATPase activity of beef heart F1 depends largely on the exposure of the enzyme to some anionic ligands such as sulphate and/or EDTA. F1 prepared in the presence of such anions exhibited a triphasic kinetic pattern whereas F1 from which those anions were removed by dialysis exhibited only two Km values for ATP. Conversely to what has been previously reported, bicarbonate did not linearize F1-ATPase kinetics. Moreover, anion activation cannot be simply explained by promotion of ADP release but mainly by an increase in affinity of the third catalytic site for ATP. 相似文献
105.
B Alexandre F Thiébaut M Allary E Boschetti C Séné J Saint-Blancard 《Revue fran?aise de transfusion et immuno-hématologie》1987,30(1):57-66
In this work the human plasma fibronectin was purified by affinity chromatography using a tandem column system. The first affinity column was filled with gelatin-Trisacryl whereas the second one contained heparin-Trisacryl. This double affinity chromatography demonstrated its high efficiency in term of purity and yield. Several analytical methods (electrophoresis, immunoelectrophoresis, F.P.L.C. and adhesion assay on cultured eucaryotic cells) evidenced in fact the high purity of the preparation as well as its biological behaviour in term of cell adhesion and spreading. The performances of the sorbents used facilitate the scaling up when large quantities of FNP are needed. 相似文献
106.
R Philipp J O McIntyre B H Robinson H Huth W Trommer S Fleischer 《Biochimica et biophysica acta》1984,790(3):251-258
Calcium efflux and EGTA-induced calcium release from an internal platelet membrane fraction have been studied after the oxalate-supported calcium uptake had reached steady state. Increasing external calcium concentrations stimulate the calcium efflux velocity, with an apparent half-maximal stimulation at about 5 microM outside calcium concentration and a maximal velocity of calcium efflux of 4.66 +/- 2.32 nmol X min-1 X mg-1. Moreover, the ratio of the liberated calcium on the loaded calcium seems to be independent of the increasing external calcium concentration. Increasing the calculated internal calcium concentration by varying the oxalate potassium concentration from 10 mM to 1 mM results in an increase of the liberated calcium from the membrane vesicles from 7.4% to 63%, respectively, without changing the calcium efflux velocity. Similar conclusions can be drawn from the observation of results from the calcium efflux and EGTA-induced calcium release methods. Moreover, calcium pump reversal does not seem to be responsible for the calcium efflux or calcium release. All these different points added to the previously described regulation of calcium efflux by the catalytic subunit of cAMP protein kinase suggest us that the mechanism of calcium liberation by the platelet membranes is different from the calcium uptake. 相似文献
107.
F Krizsa Z Borbényi E Arokszállásy I Cserháti 《Folia haematologica (Leipzig, Germany : 1928)》1980,107(4):683-687
The thrombopoietic serum activity was examined in rats during thrombocytopenia produced by bleeding or after treatment with antithrombocyte serum (ATS). 6 hours after both treatments the thrombopoietic activity of the serum, i.e. its content of thrombopoietin, is increased. After the ATS treatment of nephrectomized animals a similar increase of thrombopoietic activity as in normal animals could be achieved. In contrast to that, no similar increase of thrombopoietic activity was observed in nephrectomized animals after blood loss. According to the results of the authors the increase of thrombopoietic activity produced by different stimuli can be attributed to different mechanisms. 相似文献
108.
R Uchino T Nohara E Okamoto M Fukumoto O Midorikawa 《Virchows Archiv. B, Cell pathology including molecular pathology》1985,48(3):229-236
A cloned human hepatoma cell line (HH2-1) produced and formed collagen fibers in vitro. The relative rate of collagen synthesis by the cells was increased with an enhancement of the cell density. An analysis of the components of the collagen using sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the cells synthesized interstitial collagen, types I and III, and other collagenous proteins. Thus, human hepatoma cells may play an important role in the formation of stromal collagen in the tumor. 相似文献
109.
110.
O. V. Yagodina E. B. Nikol’skaya I. Y. Shemarova A. E. Khovanskikh 《Journal of Evolutionary Biochemistry and Physiology》2000,36(3):244-248
A comparison has been performed of catalytic properties of unicellular microorganism amine oxidases (AO) from two new enzyme
sources, the bacteriumMethanosarcina barkeri and the infusoriaTetrahymena pyriformis. It was shown that the both studied AO deaminate tyramine, serotonin, and benzylamine, but do not deaminate histamine. The
AO fromMethanosarcina barkeri catalyzes deamination of all three substrates at an identical rate, while the rate of tyramine deamination under effect of
AO fromTetrahymena pyriformis is one order higher than the rate of serotonin deamination, and about two orders higher than the rate of benzylamine deamination.
Based on the data of the substrate-inhibitor analysis, a suggestion was made about the existence of one center for the substrate
binding in the AO of the studied bacterium, while several centers in the AO of the studied infusoria. 相似文献