Inoue Hiroyuki, Sato Katsuhiko, Anzai Jun-ichi
Graduate School of Pharmaceutical Sciences, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
Biomacromolecules. 2005 Jan-Feb;6(1):27-9. doi: 10.1021/bm0495856.
A layer-by-layer thin film composed of avidin and 2-iminobiotin-labeled poly(ethyleneimine) (ib-PEI) was prepared and their sensitivity to the environmental pH and biotin was studied. The avidin/ib-PEI multilayer assemblies were stable at pH 8-12, whereas the assemblies were decomposed at pH 5-6 due to the low affinity of the protonated iminobiotin residue to avidin. The avidin/ib-PEI assemblies can be disintegrated upon addition of biotin and analogues in the solution as a result of the preferential binding of biotin or analogues to the binding site of avidin. The decomposition rate was arbitrarily controlled by changing the type of stimulant (biotin or analogues) and its concentration. The avidin/ib-PEI assemblies were disintegrated rapidly by the addition of biotin or desthiobiotin, whereas the rate of decomposition was rather slow upon addition of lipoic acid or 2-(4'-hydroxyphenylazo)benzoic acid. The present system may be useful for constructing the stimuli-sensitive devices that can release drug or other functional molecules.
制备了由抗生物素蛋白和2-亚氨基生物素标记的聚（乙烯亚胺）（ib-PEI）组成的逐层薄膜，并研究了它们对环境pH值和生物素的敏感性。抗生物素蛋白/ib-PEI多层组装体在pH 8-12时稳定，而在pH 5-6时由于质子化的亚氨基生物素残基与抗生物素蛋白的低亲和力而分解。由于生物素或类似物优先结合到抗生物素蛋白的结合位点，抗生物素蛋白/ib-PEI组装体在溶液中加入生物素和类似物后会解体。通过改变刺激物（生物素或类似物）的类型及其浓度，可以任意控制分解速率。加入生物素或脱硫生物素后，抗生物素蛋白/ib-PEI组装体迅速解体，而加入硫辛酸或2-（4'-羟基苯基偶氮）苯甲酸后分解速率相当缓慢。本系统可用于构建能够释放药物或其他功能分子的刺激敏感装置。
