Isoelectric Points of Proteins at the Air/Liquid Interface and in Solution
Electrostatic interactions play essential roles in determining the function, colloidal stability, and adsorption of proteins on different surfaces and interfaces. Therefore, a molecular-level understanding of the charge state of the proteins under different conditions is required to explain their ma...
| Publié dans: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 35(2019), 14 vom: 09. Apr., Seite 5004-5012 |
|---|---|
| Auteur principal: | |
| Autres auteurs: | , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2019
|
| Accès à la collection: | Langmuir : the ACS journal of surfaces and colloids |
| Sujets: | Journal Article Research Support, Non-U.S. Gov't Protein Aggregates Proteins Solutions |
| Résumé: | Electrostatic interactions play essential roles in determining the function, colloidal stability, and adsorption of proteins on different surfaces and interfaces. Therefore, a molecular-level understanding of the charge state of the proteins under different conditions is required to explain their macroscopic properties. In this study, we have employed an inherently surface-sensitive spectroscopic tool, sum frequency generation spectroscopy, to determine the charge state of a wide range of proteins as a function of pH at the air/liquid interface via measurement of the degree of orientation of water molecules. We compared the isoelectric point (IEP) of the 12 investigated proteins at the air/liquid interface with that in the bulk solution obtained through zeta potential measurements. Ellipsometry is performed to determine the film thickness at the air/liquid interface at different charge states. In particular, protein aggregation at the IEP is reflected by increased film thickness. For all proteins, the interfacial point of zero charge is close (with less than 1 pH unit variation) to that in the bulk solution |
|---|---|
| Description: | Date Completed 28.07.2020 Date Revised 28.07.2020 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/acs.langmuir.9b00311 |