Complex formation between bovine serum albumin and strong polyelectrolytes: Effect of polymer charge density
Complex formation between bovine serum albumin and strong polyelectrolytes: Effect of polymer charge density
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DOI：
10.1021/jp980486u
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发表时间：
1998-05-07
影响因子：
3.3
通讯作者：
Brittain, IJ
中科院分区：
文献类型：
--
作者：
Mattison, KW;Dubin, PL;Brittain, IJ
采用光散射和pH滴定法研究了牛血清白蛋白（BSA）与聚（二烯丙基二甲基氯化铵）（PDADMAC）、聚（丙烯酰胺基甲基丙基磺酸盐）（PAMPS）、聚（甲基丙烯酰胺基丙基三甲基氯化铵）（PMAPTAC）和AMPS-丙烯酰胺无规共聚物（PAMPS（80）AAm（20））的结合。发现诱导蛋白质-β-内酰胺络合所需的临界蛋白质电荷（Zpr）（c）随离子强度（I-1/2）的平方根线性变化，即，其中Debye-Huckel参数（kappa），比例常数是双链参数如固有刚度和电荷密度的函数。该线性在Zpr = 0时是显著连续的，其中（Zpr）（c）主要发生在等离子点的“错误侧”;即，当整体蛋白质电荷与电荷的符号相同时，通常观察到结合的开始。BSA与较低电荷密度聚阴离子（PAMPS（80）AAm（20））的结合出乎意料地发生在不与更高电荷的均聚阴离子（PAMPS）结合的条件下。Muthukumar的理论处理用于解释（Zpr）（c）与I-1/2的线性以及聚电解质结构参数的观察到的影响。该模型的明显适用性的异质两性蛋白质表面表明，结合的聚电解质发生在“电荷补丁”，其有效电荷密度是不同的，但仍然线性依赖于，全球电荷密度。
Light scattering and pH titration were used to examine the binding of bovine serum albumin (BSA) to poly(diallyldimethylammonium chloride) (PDADMAC), poly(acrylamidomethylpropyl sulfonate) (PAMPS), poly(methacrylamidopropyltrimethylammonium chloride) (PMAPTAC), and an AMPS-acrylamide random copolymer (PAMPS(80)AAm(20)). The critical protein charge required to induce protein-polyelectrolyte complexation, (Zpr)(c), was found to vary linearly with the square root of the ionic strength (I-1/2), i.e., with the Debye-Huckel parameter (kappa), the proportionality constant being a function of polyelectrolyte chain parameters such as intrinsic stiffness and charge density. This linearity was remarkably continuous through Zpr = 0, with (Zpr)(c) occurring predominantly "on the wrong side" of the isoionic point; i.e., the onset of binding was typically observed when the global protein charge was of the same sign as the polyelectrolyte. Binding of BSA to the lower charge density polyanion (PAMPS(80)AAm(20)) unexpectedly occurred under conditions where binding to the more highly charged homopolyanion (PAMPS) did not. The theoretical treatment of Muthukumar was used to interpret the linearity of (Zpr)(c) vs I-1/2 and the observed influence of polyelectrolyte structural parameters. The apparent applicability of this model to the heterogeneous amphoteric protein surface suggests that binding of polyelectrolytes takes place at "charge patches" whose effective charge densities are different from, but nevertheless linearly dependent on, the global charge density.