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171.
172.
G Barbato R Calabria M Cartení-Farina G D'Auria M De Rosa R Sartorio S Wurzburger V Zappia 《Biochimica et biophysica acta》1989,991(2):324-329
The interaction between S-adenosyl-L-methionine (AdoMet) and sodium poly(styrene sulfonate) NaPSS) was studied by means of ultrafiltration and ultraviolet absorption spectroscopy at several pH values and sodium sulfate concentrations. The results obtained are interpreted mainly in terms of electrostatic interactions and permit the evaluation of the binding constants under different experimental conditions. Furthermore, ultraviolet absorption spectroscopy data show a specific short-range interaction between the aromatic electronic system of AdoMet and the NaPSS aromatic ring. The results indicate that the binding strength is greatly affected by the AdoMet positive charge on the adenine ring. The other positive charges on both the sulfonic pole and the amino acidic group of AdoMet contribute only weakly to the binding to the polyanionic matrix, thus assuring some stability of AdoMet even at physiological pH. 相似文献
173.
F Lo Coco D Pasqualetti M Lopez E Panzini A Gentile R Latagliata B Monarca G De Rossi 《Blut》1989,58(5):235-240
The immunophenotype of 135 previously untreated patients with FAB defined acute myeloid leukaemia (AML) was studied at diagnosis. The panel of reagents included monoclonal antibodies (MoAb) recognising myeloid-associated determinants (CD11, CD13, CD14, CD33 and others) as well as MoAb directed towards lymphoid antigens (CD7, CD10, CD19) and TdT. The results indicate that CD13 and/or CD33 are consistently expressed in AML and only rarely in ALL blasts (131/135 + ve cases, versus 4/130 in ALL). Lymphoid antigen expression was rarely detected when CD10 and CD19 were investigated in AML (0.9% and 2% + ve cases, respectively), whereas significant positivities were found for TdT and CD7 (20% and 10% respectively). Concerning FAB subtypes, two new MoAb (LAM3 and LAM7) proved very useful in the specific recognition of AML with monocytic features. The phenotype CD13+ and/or CD33+, CD9+, HLA-DR- was found to be almost exclusive for M3 AML. The response to induction chemotherapy was analysed in CD7+ and in TdT+ patients. In the latter group a statistically significant lower response rate was found with respect to TdT-ve-AML patients. 相似文献
174.
A monoclonal antibody (2E2) produced against pectate lyase from Erwinia carotovora ssp. carotovora reacted with a 41- and a 44-kilodaltion protein on Western blots of concentrated Erwinia culture supernatants resolved by sodium dodecyl sulfate - polyacrylamide gel electrophoresis. It was unequivocally shown that monoclonal 2E2 reacted with an active form of pectate lyase by affinity purifying the antigen with the monoclonal. The affinity-purified antigen was enzymatically active and moved as a single protein band in a nonequilibrium isoelectric focusing gel. Monoclonal 2E2 reacted with the pectate lyases of a diverse range of E. carotovora ssp. carotovora, ssp. atroseptica, and ssp. betavasculorum strains, as well as with one of three strains of E. chrysanthemi. The electrophoretic mobility of the major protein (44 kilodaltons) that reacted with 2E2 was identical within a subspecies but differed among subspecies. 相似文献
175.
Peptidyl alpha-amidation activity in bovine adrenal medulla has been localized in chromaffin granules by density gradient centrifugation. The activity was found to be both soluble and membrane-associated. Both enzymatic activities were stimulated by the addition of Cu2+ and ascorbate. The pH maximum for alpha-amidation in the chromaffin granules in pH 8.0-8.5. By gel filtration, the soluble enzyme activity appeared as a protein of approx. 40 kDa. It is suggested that this enzyme is involved in the carboxyl-terminal amidation of metorphamide, amidorphin and neuropeptide Y. 相似文献
176.
H. M. Koop M. Valentijn-Benz A. V. Nieuw Amerongen P. A. Roukema J. De Graaff 《Antonie van Leeuwenhoek》1989,55(3):277-290
Twenty-seven oral strains of the genera Actinomyces (5), Bacteroides (3), and Streptococcus (19) were tested for aggregation by human whole saliva, as well as the effect of culture medium, Ca-ions, and bacteria concentration thereupon. Of the media tested, GF-broth gave rise to less interference by autoaggregation or higher aggregation titers than BHI and TSB, and was used throughout this study. In most cases, Ca-ions (1 mM) only enhanced the rate of induced aggregation, whereas raising the bacteria concentration increased the rate of both induce- and autoaggregation. The final titers, ranging from 1–64, were hardly affected by these parameters, except those of S. rattus HG 59 and S. mutans HG 199, which were respectively increased and decreased by Ca-ions. Saliva-induced aggregation was observed for 21 strains of A. viscosus, A. naeslundii, A. israelii, B. gingivalis, B. intermedius, S. cricetus, S. mutans, S. rattus, S. sanguis, and S. sobrinus, mostly within 15 min to 3 h. Seventeen of these strains also showed autoaggregation, usually well after the onset of induced aggregation. Any potential induced aggregation of B. gingivalis HG 91 was always masked by autoaggregation, as well as that of the S. mutans strains under a particular set of conditions. The aggregation rate and titer varied considerably in a mutually unrelated and strain-dependent way. These microtiterplate data were matched by the 5 spectrophotometric patterns observed for saliva-bacterial interaction, which moreover, gave the better differentiation between induced and autoaggregation. In conclusion, most strains tested can show rapid saliva-induced aggregation in a strain-dependent way, yet strongly affected by the experimental conditions and interference from autoaggregation. 相似文献
177.
Linkage analysis of chromosome 17 markers in British and South African families with neurofibromatosis type 1 下载免费PDF全文
C. G. P. Mathew K. Thorpe D. F. Easton K. S. Chin D. Jadayel M. Ponder G. Moore C. E. Wallis C. P. Slater G. De Jong P. O''''Connell R. White D. Barker B. A. J. Ponder 《American journal of human genetics》1989,44(1):38-40
Nine markers from the pericentromeric region of chromosome 17 were typed in 16 British and five South African families with neurofibromatosis type 1 (NF1). The markers--p17H8, pHHH202, and EW204--were linked to NF1 at recombination fractions less than 1%. No evidence of locus heterogeneity was detected. Inspection of recombinant events in families informative for several markers suggests that the NF1 gene is located between the markers EW301 (cen-p11.2) and EW206 (cen-q12) and possibly distal to pHHH202 (q11.2-q12). 相似文献
178.
I De Dios J J Calvo J I San Roman M A Plaza M A Lopez 《Archives internationales de physiologie et de biochimie》1989,97(1):37-43
The effect of Dobutamine (a beta 1-adrenergic agonist) and Terbutaline (a beta 2-adrenergic agonist) on exocrine pancreatic secretion was studied in anaesthetized rabbits, simultaneously controlling pancreatic blood flow and blood pressure. The secretion of fluid and ions (bicarbonate, sodium and potassium) was unaffected by the infusion of Dobutamine (8 micrograms.kg-1.min-1) or Terbutaline (10 micrograms.kg-1.min-1). Neither were pancreatic blood flow or mean blood pressure altered. Dobutamine or Terbutaline depress the function of the acinar cells, amylase secretion being more affected by the action of Terbutaline. The results show that beta 1 and beta 2-adrenergic stimulation has no effect on the ductular cells but does decrease the secretion by the acinar cells. 相似文献
179.
180.
Identification and purification of the tricarboxylate carrier from rat liver mitochondria 总被引:1,自引:0,他引:1
The tricarboxylate carrier from rat liver mitochondria was solubilized with Triton X-100 and purified by chromatography on hydroxyapatite and celite. SDS-gel electrophoresis of the purified fraction showed a single polypeptide band with an apparent Mr of 30,000. When reconstituted into liposomes, the tricarboxylate transport protein catalyzed a 1,2,3-benzenetricarboxylate-sensitive citrate/citrate exchange. We obtained a 1070-fold purification with respect to the mitochondrial extract, the recovery was 22% and the protein yield 0.02%. The properties of the reconstituted carrier, i.e., requirement for a counteranion, substrate specificity and inhibitor sensitivity, were similar to those of the tricarboxylate transport system as characterized in intact mitochondria. 相似文献