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    • 2. 发明授权
    • Transesterification of insoluble polysaccharides
    • 不溶性多糖的酯交换
    • US6063916A
    • 2000-05-16
    • US774329
    • 1996-11-27
    • Joseph A. AkkaraDavid L. KaplanFerdinando F. BrunoJonathan S. Dordick
    • Joseph A. AkkaraDavid L. KaplanFerdinando F. BrunoJonathan S. Dordick
    • C12P7/62C08B3/00C08B31/02C08B37/00
    • C12P7/625
    • Bacillus subtilis protease catalyzes the acylation of organic solvent-insoluble polysaccharides in isooctane solution containing vinyl esters of fatty acids as acyl donor. The reaction occurs only when the enzyme is solubilized via ion-pairing with the anionic surfactant dioctyl sulfosuccinate, sodium salt (AOT). Enzyme based acylation was demonstrated with amylose, cyclodextrins, cellulose, cellulose derivatives, and other polysaccharides such as chitosan, pullulan, and maltodextrose. These polysaccharides are reactive either as a cryogenically milled powder suspended in the organic solvent or as a thin film deposited onto ZnSe slides. For chitosan, .alpha.-cyclodextrin, and hydroxyethyl cellulose (HEC), the enzymatic crosslinking reaction occurs using adipic acid divinyl ester (C6DVE). HEC forms a compound that gels in solvents such as ethyl alcohol and dimethyl sulfone oxide (DMSO). Electron spectroscopy chemical analysis (ESCA) of the first 100 .ANG. of the amylose thin film amylose indicates that the acylated surface had a degree of substitution of 0.9.+-.0.1 acyl chains per glucose moiety and this corresponded well to the expected regioselectivity of subtilisin catalysis on glucose-containing compounds. .sup.1 H-NMR studies indicated that only the C-6 hydroxyl groups of the glucose moiety were acylated with amylose and .gamma.-cyclodextrin. However, .beta.-cyclodextrin, and .alpha.-cyclodextrin were modified at secondary alcohols and at all three alcohols, respectively. This approach represents the first attempt at using enzymes to modify organic solvent-insoluble polymers in nonaqueous media.
    • 枯草芽孢杆菌蛋白酶催化有机溶剂不溶性多糖在含有作为酰基供体的脂肪酸乙烯基酯的异辛烷溶液中的酰化。 仅当酶通过离子配对与阴离子表面活性剂二辛基磺基琥珀酸钠(AOT)溶解时才发生反应。 用直链淀粉,环糊精,纤维素,纤维素衍生物和其它多糖例如壳聚糖,支链淀粉和麦芽糊精证明酶基酰化。 这些多糖作为悬浮在有机溶剂中的低温研磨粉末或沉积在ZnSe载片上的薄膜是反应性的。 对于壳聚糖,α-环糊精和羟乙基纤维素(HEC),使用己二酸二乙烯基酯(C 6 DVE)发生酶交联反应。 HEC形成在溶剂如乙醇和二甲基砜氧化物(DMSO)中凝胶化合物。 直链淀粉薄膜直链淀粉的前100个ANGSTROM的电子光谱化学分析(ESCA)表明,酰化表面的每个葡萄糖部分的取代度为0.9 +/- 0.1个酰基链,这与枯草杆菌蛋白酶催化的预期区域选择性相当 对含葡萄糖的化合物。 1 H-NMR研究表明,只有葡萄糖部分的C-6羟基被直链淀粉和γ-环糊精酰化。 然而,β-环糊精和α-环糊精分别在仲醇和所有三种醇上进行了改性。 该方法代表了使用酶来修饰非水介质中有机溶剂不溶性聚合物的第一次尝试。