Protein adsorption to poly(ethylenimine)-modified Sepharose FF: II. Effect of ionic strength
Protein adsorption to poly(ethylenimine)-modified Sepharose FF: II. Effect of ionic strength
复制标题
蛋白质对聚（乙烯亚胺）修饰的 Sepharose FF 的吸附：II。
DOI：
10.1016/j.chroma.2013.07.016
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发表时间：
2013
影响因子：
4.1
通讯作者：
Yan Sun
中科院分区：
文献类型：
--
作者：
Lin-Ling Yu;Yan Sun
在本工作的第一部分中，我们研究了离子容量（IC）对聚乙烯亚胺（PEI）接枝Sepharose FF吸附牛血清白蛋白（BSA）平衡和动力学的影响，发现了一个临界IC（cIC，600 mmol/L），超过此IC，蛋白容量和吸附速率都急剧增加。本工作选择了五种具有代表性的离子交换树脂PEI-Sepharose FF，研究了离子强度对BSA吸附平衡和动力学的影响。使用市售的DEAE（IC = 160 mmol/L）和Q Sepharose FF（IC = 269 mmol/L）树脂进行比较。结果表明，在离子容量相近的条件下，PEI-Sepharose FF树脂和市售树脂对蛋白质的吸附容量均随离子交换容量的增加而降低，但在对盐浓度的敏感性方面，前者低于后者。此外，前者的有效扩散系数（De）小于后者在整个IS范围内研究。PEI-Sepharose FF树脂的吸附容量的低IS敏感性可以通过随着IS增加而增加的孔可及性来解释;认为PEI-Sepharose FF树脂中较小的Develes是由于低PEI密度的PEI-Sepharose FF树脂中缺乏表面扩散。对于高IC（520、740和1220 mmol/L）的PEI-Sepharose FF树脂，其蛋白容量和降解量均随IS的增加先增加后降低。低IS范围内蛋白质容量的增加趋势被认为是由于BSA的可及孔的增加。DE的升降趋势归因于“链传递”效应对蛋白质容量和结合强度的依赖性，这两者都与IS有关。此外，对于IC> cIC（740和1220 mmol/L）的树脂，其IS灵敏度远高于IC < cIC的树脂，进一步证明了在IC > cIC时，PEI层中的“链传递”效应确实对总传质有显著贡献。ICs > cIC的PEI-Sepharose FF树脂对200-300 mmol/L的NaCl溶液仍保持较高的吸附容量。因此，这两种PEI-Sepharose FF树脂的操作IS范围可比传统离子交换介质宽得多。
In Part I of this work, we have studied the effect of ionic capacity (IC) on bovine serum albumin (BSA) adsorption equilibria and kinetics to poly(ethylenimine) (PEI)-grafted Sepharose FF, and found a critical IC (cIC, 600 mmol/L), above which both protein capacity and uptake rate increased drastically. In this work, five PEI-Sepharose FF resins of typical ICs reported earlier were selected to explore the effect of ionic strength (IS) on the adsorption equilibria and kinetics of BSA. Commercially available DEAE (IC = 160 mmol/L) and Q Sepharose FF (IC = 269 mmol/L) resins were used for comparisons. It is found that at similar ionic capacities, protein adsorption capacities on both the PEI-Sepharose FF resins and the commercial resins decreased with increasing IS, but on the capacity sensitivity to salt concentration, the former was lower than the latter. In addition, the effective diffusivities (De) of the former were smaller than the latter in the entire IS range studied. The low IS sensitivity of adsorption capacity of the PEI-Sepharose FF resins could be interpreted by the increase of pore accessibility with increasing IS; the smallerDevalues in the PEI-Sepharose FF resins were considered due to the lack of surface diffusion in the PEI-Sepharose FF resins of low PEI densities. For the PEI-Sepharose FF resins of high ICs (520, 740 and 1220 mmol/L), both protein capacity andDevalues increased first and then decreased with increasing IS. The increasing trend of protein capacity in the low IS range was considered due to the increase of accessible pores for BSA. The rise–fall trend ofDewas attributed to the dependencies of the “chain delivery” effect on protein capacity and binding strength, both of which are related to IS. Moreover, the IS sensitivity of theDefor the resins of ICs > cIC (740 and 1220 mmol/L) was much higher than those of ICs < cIC, further proving that the “chain delivery” effect in PEI layer did contribute significantly to the overall mass transfer at IC > cIC. Furthermore, the two PEI-Sepharose FF resins of ICs > cIC kept high adsorption capacities andDevalues up to 200–300 mmol/L NaCl. Therefore, the operating IS ranges for these two PEI-Sepharose FF resins can be much broader than the traditional ion-exchange media.