Adsorption Mechanism at the Molecular Level between Polymers and Uremic Octapeptide by the 2D 1H NMR Technique

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• 作者：Guohua Li ; Jihong Li ; Wei Wang ; MeiYang ; Yuanwei Zhang ; Pingchuan Sun ; Zhi Yuan ; Binglin He ; and Yaoting Yu
• 刊名：Biomacromolecules
• 出版年：2006
• 出版时间：June 2006
• 年：2006
• 卷：7
• 期：6
• 页码：1811 - 1818
• 全文大小：349K
• 年卷期：v.7,no.6(June 2006)
• ISSN：1526-4602

文摘

To remove uremic octapeptide from the blood stream of uremic patients, various modified polyacylamide cross-linked absorbents were prepared. Adsorption experiments showed these absorbents have significant differencesin adsorption capacity to the target peptide. In this paper, two-dimension proton nuclear magnetic resonance (2D¹H NMR) spectroscopy was used to investigate the interaction mechanism between the peptide and the adsorbents.Because of the insolubility of the absorbent, some soluble linear polymers with the same functional groups as theabsorbents were employed as the model adsorbents in 2D ¹H NMR. The preferred binding site for the peptideand polymers was identified to be at the C-terminal carboxyl group of the octapeptide via chemical shift perturbationeffects. In this study, we found that hydrogen bonding, electrostatic, and hydrophobic interactions all play a rolein the interaction force but had different contributions. Especially, the great chemical shift changes of the aromaticamino acid residues (Trp) during the interaction between butyl-modified polyacrylamide and octapeptide suggestedthe hydrophobic interaction, incorporated with the electrostatic force, played an important role in the bindingreaction in aqueous solutions. This information not only rationally explained the results of the adsorptionexperiments, but also identified the effective binding site and mechanism, and shall provide a structural basis fordesigning better affinity-type adsorbents for the target peptide.