Finette G M, Baharin B, Mao Q M, Hearn M T
Centre for Bioprocess Technology, Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, 3168 Victoria, Australia.
Biotechnol Prog. 1998 Mar-Apr;14(2):286-93. doi: 10.1021/bp9800034.
The influences of the fluid superficial velocity, sample concentration, loading volume, and wash cycle on the recovery and corresponding purification factors for alpha1-antitrypsin [syn. alpha1-proteinase inhibitor (alpha1-PI)] from crude mixtures of human plasma proteins were investigated using packed and expanded beds of DEAE-Spherodex LS. As part of this study, the effect of fluid superficial velocity on the bed dispersion number (Dv) and dispersion coefficient (D) for this adsorbent in expanded beds was determined with feedstocks containing human serum albumin (HSA), the most abundant of the contaminating proteins in human plasma protein preparations used for the isolation of alpha1-PI. When multicomponent protein feedstocks prepared from human plasma were examined with DEAE-Spherodex LS, reduced chromatographic productivity was observed for alpha1-PI as the extent of column utilization and the superficial velocity were increased, yet the opposite trend was evident for HSA. In particular, higher adsorption capacities and recoveries were obtained for alpha1-PI at lower fluid superficial velocities with both packed and expanded bed conditions. These findings indicate that for process scale purifications of alpha1-PI from multicomponent feedstocks with expanded beds containing this silica-based ion-exchange adsorbent, the optimal range of superficial velocities to achieve the highest bed productivity will not be synonymous with maximally fluidized modes of operation. Rather, the results confirm that the adsorbent has an optimum operational performance when fluidization procedures corresponding to plug flow expansion are employed for the capture of alpha1-PI. These findings also indicate that advantage can be taken of displacement effects between closely related protein species with packed and expanded bed systems containing the DEAE-Spherodex LS type of ion-exchange porous silicas.
使用DEAE-Spherodex LS填充床和膨胀床，研究了流体表观流速、样品浓度、进样体积和洗涤循环对从人血浆蛋白粗混合物中回收α1-抗胰蛋白酶[同义词：α1-蛋白酶抑制剂(α1-PI)]及其相应纯化因子的影响。作为本研究的一部分，用含有人血清白蛋白(HSA)的原料测定了流体表观流速对该吸附剂在膨胀床中的床层分散数(Dv)和分散系数(D)的影响，HSA是用于分离α1-PI的人血浆蛋白制剂中最丰富的污染蛋白。当用DEAE-Spherodex LS检测由人血浆制备的多组分蛋白质原料时，随着柱利用率和表观流速的增加，观察到α1-PI的色谱生产率降低，而HSA则呈现相反的趋势。特别是，在填充床和膨胀床条件下，较低的流体表观流速下α1-PI具有更高的吸附容量和回收率。这些发现表明，对于使用含有这种硅基离子交换吸附剂的膨胀床从多组分原料中进行工艺规模纯化α1-PI而言，实现最高床层生产率的最佳表观流速范围并不等同于最大流化操作模式。相反，结果证实，当采用对应于活塞流膨胀（plug flow expansion）的流化程序捕获α1-PI时，吸附剂具有最佳操作性能。这些发现还表明，对于含有DEAE-Spherodex LS型离子交换多孔硅胶的填充床和膨胀床系统，可以利用密切相关蛋白质物种之间的置换效应。
