Effect of enzyme location on activity and stability of trypsin and urease immobilized on porous memb
Effect of enzyme location on activity and stability of trypsin and urease immobilized on porous memb
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DOI：
10.1016/j.memsci.2010.08.042
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发表时间：
2010-12
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通讯作者：
S. Guedidi;Yilmaz Yurekli;A. Deratani;P. Déjardin;C. Innocent;S. A. Altinkaya;S. Roudesli;A. Yemenicioğlu
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文献类型：
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作者：
S. Guedidi;Yilmaz Yurekli;A. Deratani;P. Déjardin;C. Innocent;S. A. Altinkaya;S. Roudesli;A. Yemenicioğlu
聚电解质的逐层自组装是将酶固定在膜上最简单的方法之一。本文介绍了用LBL组装技术在聚丙烯腈基膜上固定化胰酶(Try)和尿素酶(Ure)。所研究的体系是以酶层为外层的双层组装和以酶层为内夹层的三层组装。膜孔径的选择使得较小的酶Try主要固定在膜内，并限制在多孔膜结构中，而Ure的固定化主要发生在膜表面。这两种酶的活性没有显著差异。固定化酶的催化活性低于溶液中的游离酶，但其稳定性显着提高。当酶作为LBL组件的外层沉积时，观察到较高的活性。另一方面，当外层由覆盖在酶层上的聚电解质组成时，得到的催化膜更稳定。
The layer-by-layer (LbL) self-assembly of polyelectrolyte is one of the simplest ways to immobilize enzyme on membrane. In this paper, the immobilization of trypsin (TRY) and urease (URE) on polyacrylonitrile based membranes using the LbL assembly technique was presented. The studied systems consisted in bilayered assemblies with the enzyme layer as the outer layer and trilayered assemblies with the enzyme layer as the inner sandwiched layer. The membrane pore size was chosen so that the smaller enzyme TRY was mainly immobilized within the membrane and confined in the porous membrane structure while URE immobilization mainly took place at the membrane surface. No dramatic difference on reactivity was evidenced between these two enzyme locations. The catalytic activity of immobilized enzymes was found to be lower than the free ones in solution but their stability was dramatically enhanced. The higher activity was observed when the enzyme is deposited as the outer layer of the LbL assembly. On the other hand, the more stable catalytic membranes were obtained when the outer layer consists of a polyelectrolyte covering the enzyme layer.