The adsorption from solutions of β-lactoglobulin mixed with lactoferrin or lysozyme onto silica and methylated silica surfaces
Wahlgren, Marie C. LU
; Arnebrant, Thomas
and Paulsson, Marie A.
LU
(1993)
In Journal of Colloid and Interface Science
158(1).
p.46-53
- Abstract
The adsorption from pure protein solutions and binary mixtures of proteins with opposite net charges was studied at pH 7 by in situ ellipsometry. The investigated proteins were β-lactoglobulin, lactoferrin, and lysozyme. On hydrophilic silica surfaces, β-lactoglobulin (negatively net charged) adsorbed in small amounts while lactoferrin and lysozyme (both positively net charged) adsorbed in higher quantities. All the proteins adsorbed readily to the methylated silica surfaces. On both surfaces the amounts of β-lactoglobulin adsorbed were higher and the ones for lactoferrin and lysozyme were lower in a high ionic strength buffer (I = 0.17 M) compared to a buffer with low ionic strength (I = 0.02 M). In... (More)
The adsorption from pure protein solutions and binary mixtures of proteins with opposite net charges was studied at pH 7 by in situ ellipsometry. The investigated proteins were β-lactoglobulin, lactoferrin, and lysozyme. On hydrophilic silica surfaces, β-lactoglobulin (negatively net charged) adsorbed in small amounts while lactoferrin and lysozyme (both positively net charged) adsorbed in higher quantities. All the proteins adsorbed readily to the methylated silica surfaces. On both surfaces the amounts of β-lactoglobulin adsorbed were higher and the ones for lactoferrin and lysozyme were lower in a high ionic strength buffer (I = 0.17 M) compared to a buffer with low ionic strength (I = 0.02 M). In mixtures of β-lactoglobulin and lactoferrin the proteins interact leading to high adsorbed amounts on the silica surface and to complete irreversibility with respect to rinsing with buffer. The effect is reduced by increasing the ionic strength of the buffer and by decreasing the overall concentration of proteins in the bulk. This is interpreted in terms of electrostatic interactions between the two proteins. The adsorbed amount from a β-lactoglobulin/lactoferrin mixture to a methylated silica surface is between the amounts for the pure proteins, and the adsorbate is a mixture of lactoferrin and β-lactoglobulin as indicated by measurements with radioactively labeled lactoferrin. An interesting observation was that the adsorbed amount from a β-lactoglobulin/lactoferrin mixture onto a methylated silica surface increased upon rinsing at high bulk concentrations and at low ionic strength. The adsorption from mixtures of β-lactoglobulin and lysozyme is also strongly influenced by electrostatic interactions. At low ionic strength a bulk precipitation takes place, which probably is the reason for the very high amounts adsorbed onto both surfaces examined. This effect is only partially reduced at higher ionic strength.
(Less)
- author
- Wahlgren, Marie C.
LU
; Arnebrant, Thomas
and Paulsson, Marie A.
LU
- organization
- publishing date
- 1993
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Colloid and Interface Science
- volume
- 158
- issue
- 1
- pages
- 8 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:0003025269
- ISSN
- 0021-9797
- DOI
- 10.1006/jcis.1993.1227
- language
- English
- LU publication?
- yes
- id
- 4a376f05-6e52-43a8-8a4f-dec4d71729e3
- date added to LUP
- 2018-12-16 10:35:22
- date last changed
- 2023-09-08 14:06:35
@article{4a376f05-6e52-43a8-8a4f-dec4d71729e3,
abstract = {{<p>The adsorption from pure protein solutions and binary mixtures of proteins with opposite net charges was studied at pH 7 by <i>in situ</i> ellipsometry. The investigated proteins were β-lactoglobulin, lactoferrin, and lysozyme. On hydrophilic silica surfaces, β-lactoglobulin (negatively net charged) adsorbed in small amounts while lactoferrin and lysozyme (both positively net charged) adsorbed in higher quantities. All the proteins adsorbed readily to the methylated silica surfaces. On both surfaces the amounts of β-lactoglobulin adsorbed were higher and the ones for lactoferrin and lysozyme were lower in a high ionic strength buffer (<i>I</i> = 0.17 <i>M</i>) compared to a buffer with low ionic strength (<i>I</i> = 0.02 <i>M</i>). In mixtures of β-lactoglobulin and lactoferrin the proteins interact leading to high adsorbed amounts on the silica surface and to complete irreversibility with respect to rinsing with buffer. The effect is reduced by increasing the ionic strength of the buffer and by decreasing the overall concentration of proteins in the bulk. This is interpreted in terms of electrostatic interactions between the two proteins. The adsorbed amount from a β-lactoglobulin/lactoferrin mixture to a methylated silica surface is between the amounts for the pure proteins, and the adsorbate is a mixture of lactoferrin and β-lactoglobulin as indicated by measurements with radioactively labeled lactoferrin. An interesting observation was that the adsorbed amount from a β-lactoglobulin/lactoferrin mixture onto a methylated silica surface increased upon rinsing at high bulk concentrations and at low ionic strength. The adsorption from mixtures of β-lactoglobulin and lysozyme is also strongly influenced by electrostatic interactions. At low ionic strength a bulk precipitation takes place, which probably is the reason for the very high amounts adsorbed onto both surfaces examined. This effect is only partially reduced at higher ionic strength.</p>}},
author = {{Wahlgren, Marie C. and Arnebrant, Thomas and Paulsson, Marie A.}},
issn = {{0021-9797}},
language = {{eng}},
number = {{1}},
pages = {{46--53}},
publisher = {{Elsevier}},
series = {{Journal of Colloid and Interface Science}},
title = {{The adsorption from solutions of β-lactoglobulin mixed with lactoferrin or lysozyme onto silica and methylated silica surfaces}},
url = {{http://dx.doi.org/10.1006/jcis.1993.1227}},
doi = {{10.1006/jcis.1993.1227}},
volume = {{158}},
year = {{1993}},
}