Protein adsorption to (3-acrylamido propyl) trimethyl ammonium chloride-grafted Sepharose gel: Charge density reduction via copolymerizing with electroneutral monomer drastically increases uptake rate.
Protein adsorption to (3-acrylamido propyl) trimethyl ammonium chloride-grafted Sepharose gel: Charge density reduction via copolymerizing with electroneutral monomer drastically increases uptake rate.
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DOI：
10.1016/j.chroma.2020.461483
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发表时间：
2020-08
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影响因子：
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通讯作者：
Linling Yu;Rui Xu;Xiaoyan Dong;Yang Liu;Y. Sun
中科院分区：
文献类型：
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作者：
Linling Yu;Rui Xu;Xiaoyan Dong;Yang Liu;Y. Sun
聚合物接枝到多孔材料上是制造高容量和高吸收率蛋白质离子交换剂的有效方法，因为聚合物离子交换基团的三维结构提供了高结合空间，促进了结合蛋白质的运输。本文通过在Sepharose FF凝胶上接枝（3-丙烯酰胺丙基）三甲基氯化铵（APTAC）制备了一种新的阴离子交换剂，用于蛋白质吸附和层析。由于阳离子聚合物链的高电荷密度，离子交换剂FF-pAPTAC在牛血清白蛋白（BSA）吸附中具有高容量但吸收率有限的特点。为了解决这一问题，我们提出将APTAC与电中性单体丙烯酰胺（AM）共聚到Sepharose FF上，以调节接枝聚合物链的电荷密度。降低APTAC与AM的投料摩尔比，共聚树脂的离子容量（IC） FF-p(AM-APTAC)n （n为IC，单位为mmol/L）降低，但由于两种单体的反应性比相近，其链长基本保持不变。随着IC的降低，由于蛋白质结合位点的减少，FF-p(AM-APTAC)n的静态吸附量（qm）逐渐降低。而吸收速率（有效孔隙扩散率与自由溶液扩散率之比De/D0）则随着IC的降低呈现出明显的上升趋势，达到了FF-pAPTACn最大吸收速率的2.5倍。认为电荷密度的降低削弱了蛋白质与链的结合强度，增加了链的柔韧性，从而促进了结合蛋白在链上的运输。此外，在相同的IC下，每个FF-p(AM-APTAC)n与FF-pAPTACn相比具有相似的吸附容量和较高的吸收率，这主要是由于共聚物的链长较长。特别是在IC = 50±2 mmol/L时，de / d0增加了约6.5倍。高吸附量和高吸收率使FF-p（AM-APTAC n）表现出优异的动态结合性能。研究结果表明，通过共聚电中性单体来降低链电荷密度是制备高性能蛋白质离子交换剂的理想方法。
Polymer-grafting to porous materials is an effective way to create protein ion-exchangers of high capacity and uptake rate because the 3D architecture of the polymeric ion exchange groups provides high binding space and facilitated transport of the bound protein. Herein, a new anion exchanger was fabricated by grafting (3-acrylamide propyl) trimethyl ammonium chloride (APTAC) onto Sepharose FF gel for protein adsorption and chromatography. The ion exchanger, denoted as FF-pAPTAC, presented high capacity but limited uptake rate in bovine serum albumin (BSA) adsorption due to the high charge density of the cationic polymer chains. To solve the problem, we proposed to copolymerize APTAC with an electroneutral monomer, acrylamide (AM), onto Sepharose FF to modulate the charge density of the grafted polymer chains. By decreasing the feeding molar ratio of APTAC to AM, the ionic capacity (IC) of the copolymerized resins, FF-p(AM-APTAC)n (n denotes IC in mmol/L), decreased, but the chain length could be remained almost unchanged due to the similar reactivity ratios of the two monomers. With decreasing IC, the static adsorption capacity (qm) of FF-p(AM-APTAC)n decreased gradually because of the decline of protein binding sites. The uptake rate, however, represented by the ratio of effective pore diffusivity to the free solution diffusivity (De/D0), exhibited a strong uptrend with decreasing IC, reaching ~2.5-fold of the maximum observed with FF-pAPTACn. It is considered that the decrease of charge density weakened protein binding strength to the chains and increased the chain flexibility, which consequently facilitated the transport of bound proteins on the chains. Moreover, at the same IC, each FF-p(AM-APTAC)n displayed similar adsorption capacity but high uptake rate as compared with its FF-pAPTACn counterpart mainly due to the longer chain length of the copolymer. Particularly, ~6.5-fold enhancement ofDe/D0was observed at IC = 50 ± 2 mmol/L. Both high adsorption capacity and uptake rate made FF-p(AM-APTAC)n exhibit superior dynamic binding performance. The findings proved that reducing chain charge density by copolymerizing an electroneutral monomer was promising for fabrication of high-performance protein ion exchangers.