Assuntos
RNA Polimerases Dirigidas por DNA/metabolismo , DNA/metabolismo , Escherichia coli/enzimologia , Fluorescência , RNA Bacteriano/metabolismo , Sequência de Bases , DNA/química , RNA Polimerases Dirigidas por DNA/genética , Escherichia coli/genética , Corantes Fluorescentes , Regulação Bacteriana da Expressão Gênica , RNA Bacteriano/genética , Espectrometria de FluorescênciaRESUMO
It has been shown that platelet-activating factor (PAF) specimens prepared via acetylation of 1-alkyl-sn-glycero-3-phosphocholine (lyso-PF) with acetic anhydride are heterogeneous. The contaminated compound was isolated and identified to be the structural isomer of PAF, 1-alkyl-3-acetyl-sn-glycero-2-phosphocholine (iso-PAF). It appeared, that iso-PAF is formed when performing the reaction in the presence of organic bases,but not under acid catalysis. The mechanism of iso-PAF formation is discussed.
Assuntos
Fator de Ativação de Plaquetas/análogos & derivados , Fator de Ativação de Plaquetas/síntese química , Acetilação , Espectroscopia de Ressonância Magnética , Conformação Molecular , Fator de Ativação de Plaquetas/químicaRESUMO
In studying acetylation of 1-alkyl-sn-glycero-3-phosphocholine (lyso PAF) with acetic anhydride, a key step of the platelet activating factor (PAF) synthesis, we have found that in the presence of triethylamine or 4-dimethylaminopyridine some 1-alkyl-3-acetyl-sn-glycero-2-phosphocholine as an admixture to PAF formed, whereas the acid catalysed reaction resulted in isomerically pure PAF. The mechanism of the reaction leading to the PAF structural isomer is discussed.
