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DeAe mechanism

Both the Se2 (front) and Se2 (back) mechanisms are designated DeAe in the lUPAC system. With substrates in which we can distinguish the possibility, the former mechanism should result in retention of configuration and the latter in inversion. The reaction of allylsilanes with adamantyl chloride and TiCU, for example, gives primarily the antiproduct via a Se2 reaction. When the electrophile attacks from the front, there is a third possibility. A portion of the electrophile may assist in the removal of the leaving group, forming a bond with it at the same time that the new C—Y bond is formed... [Pg.760]

Phospholipase A activity was subsequently demonstrated to be present in venom, and it too required Ca (25). DEAE-cellulose fractionation yielded four proteins, two of which were phospholipase A and hemolytic, and two of which had neither phospholipase A nor hemolytic activities. Either of the latter two proteins enhanced to various degrees the hemolytic activity of either of the two phospholipases. The findings suggest considerable analogy with synergistic mechanisms underlying the hemolytic action of the venoms of a number of snakes. [Pg.310]

Transfection is the process of introducing DNA or RNA into eukaryotic ceils. The use of transfection is to study the role and regulation of proteins or to understand the mechanisms of a pathway. Transfection can be transient for rapid analysis or stable , mostly for induction of expression. There are various methods of transfection which include electroporation, viral vectors, DEAE-Dextran, calcium phosphate or Lipofectamine. The choice of transfection depends on the cell type used. The most desirable technique is the one which gives high efficiency of nucleic acid transfection with less interference to the cells physiology and high reproducibility. [Pg.64]

The reaction of the same compound with acetic acid-perchloric acid seems to proceed by an Se2 mechanism (IUPAC designation l/3/DEAE) 31... [Pg.577]

Both the Se2 (front) and Se2 (back) mechanisms are designated DeAe in the lUPAC system. With substrates in which we can distinguish the possibility, the former... [Pg.753]

Yagura et al. [20] have reported that various eukaryotic cells contain at least two forms of DNA polymerase a. One possessed an ability to synthesize poly(dA) with poly(dT) as template and without primer in the presence of ATP and dATP [21]. They also showed that the unique property of this enzyme was due to the association of DNA primase activity with this enzyme [22]. As shown in Fig. 5, when bovine thymus DNA polymerase a fraction obtained from phosphocellulose column chromatography was further purified by DEAE-Sephadex A-50 column chromatography, the enzyme activity was separated into two major sharp peaks. Since one of the peaks was associated with the primase activity, we call this fraction DNA polymerase a with primase (DNA pol a-primase) and the other (fraction II in Fig. 5) DNA polymerase a in this study. When these two enzyme fractions were incubated in a reconstituted poly(ADP-ribos)ylating system, both DNA pol a-primase and DNA polymerase a were strongly inhibited (77 and 50% inhibition, respectively, Table 1). Thus, in order to clarify the mechanism of the inhibition, further study was carried out using mainly the DNA pol a-primase fraction. All the components of poly(ADP-ribos)ylation... [Pg.87]

Cell sap contains a specific phosphoprotein phosphatase (P) which dephosphoiylates protein 67, eIF-2 and several other dsRNA-dependent phosphorylated proteins (5). The protein phosphatase P is separated from PK-i on DEAE-cellulose and elutes at 25O1DM KCl. As shown in Figure 5> P stimulates mengo RNA translation in interferon-treated cell extracts (SlO-int) supplemented with dsRNA, but not in control cell extracts (SIO-cont). This suggests a regulatory mechanism which controls the level of PK-i dependent inhibition of protein synthesis. [Pg.243]

The L-cells did not respond to 10 yg/ml of plain poly I poly C, but those cultures that had DEAE-Dx in addition to the poly I-poly C yielded 300 units of interferon per ml. The mechanism of this enhancement, however, appears to be complex. One can prepare a complex of poly I poly C with DEAE-Dx simply by mixing the two in proper proportions. Such a complex is more resistant to hydrolysis by RNase than is plain poly I-poly C. When this dextran complex is administered to mice it elicits 10 times more serum interferon than does poly I poly C. It is also more effective in L-cells than is the uncomplexed d.s. RNA. [Pg.36]

DEAE-cellulose has been reported to undergo irreversible binding, via a base-pairing mechanism, with poly(vinyl alcohol) substituted with oligo(deoxy-thymidine 5 -phosphate). It was possible to separate mixtures of synthetic oligonucleotides using the complexed cellulose derivative as an aflSnity-chromatography matrix. [Pg.435]

Wittmann, G. Dietzschold, B. Bauer, K. (1975).Some investigations on the adjuvant mechanism of DEAE-Dextran, Arch. Virol.,47,225-235. [Pg.193]

Eshita, Y. Higashihara, J. Onishi, M. Mizuno, M. Yoshida, J. Takasaki, . Kubota, N. Onishi, Y. (2009).Mechanism of Introducing ExogenousGenes into Cultured Cells Using DEAE-Dextran- MMA Graft Copolymer as Non-Viral Gene Carrier, Molecules,14,2669-2683. [Pg.195]


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See also in sourсe #XX -- [ Pg.570 ]




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