The mobility of tryptophan fluorophore in N-butyl-Nα-acetyltryptophanamide and in side chain of labelled poly(N-ethylacrylamide) and poly(N-ethylmethacrylamide) was investigated by the fluorescence depolarization method. The mobility of the fluorophore in the low-molecular-weight model is much higher than in side chains of the polymers. Different steric hindrance by the polymer backbone can explain the higher mobility of the fluorophore in poly(N-ethylacrylamide) and in poly(N-ethylmethacrylamide). The mobility of 5-dimethylamino-1-naphthalenesulfonamide (dansyl) fluorophore in side chains of labelled poly(N-ethylmethacrylamide) in the high-viscosity range increases with increasing number of methylene groups in side chains. The low-viscosity range, the rate s of conformational changes in short side chains (n = 2 - 7) are approximately constant and significantly decrease in long side chains (n = 10, 12). The drop in the rates is probably due to intramolecular association of the long hydrophobic chains in water.
采用荧光偏振法研究了N-丁基-Nα-乙酰色氨酸酰胺和标记聚(N-乙基丙烯酰胺)和聚(N-乙基甲基丙烯酰胺)侧链中色氨酸荧光团的运动性。低分子量模型中荧光团的运动性比聚合物侧链中的高得多。聚合物骨架的不同立体位阻可以解释聚(N-乙基丙烯酰胺)和聚(N-乙基甲基丙烯酰胺)中荧光团的运动性更高。标记的聚(N-乙基甲基丙烯酰胺)侧链中5-二甲基氨基-1-萘磺酰胺(dansyl)荧光团在高粘度范围内的运动性随着侧链中亚甲基基团数量的增加而增加。在低粘度范围内,短侧链(n = 2-7)的构象变化速率s大致保持不变,在长侧链(n = 10, 12)中显着降低。速率的下降可能是由于长的疏水侧链在水中的分子内缔合所致。