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Use of polyvalent cations to improve the adsorption strength between adsorbed enzymes and supports coated with dextran sulfate

Paper ID Volume ID Publish Year Pages File Format Full-Text
18330 42718 2006 5 PDF Available
Title
Use of polyvalent cations to improve the adsorption strength between adsorbed enzymes and supports coated with dextran sulfate
Abstract

In this paper, we have shown that the presence of low concentrations of trivalent cations during the adsorption of proteins on supports coated with dextran sulfate strongly reinforces the adsorption strength of the proteins, without altering the enzyme activity. This makes much more difficult its desorption (in some cases, the protein remained fully adsorbed under conditions where the conventional immobilized enzymes have been fully desorbed), and in this way, enabling their use in a wider range of conditions. This may be explained if the trivalent cation forms an ionic bridge between the two charges of the sulfate group and the charge of aspartic or glutamic residues. The presence of moderate (e.g., 5–10 mM) of these cations during use may further reinforce the adsorption of the proteins, increasing by a 20–40%, the concentration of NaCl necessary to desorb 50% of the adsorbed proteins. Moreover, the enzymes immobilized under these conditions exhibited an improved stability in thermal and organic solvent inactivations (e.g., penicillin acylase improved its thermal stability by a six-fold factor).

Keywords
Reversible immobilization of proteins; Stabilization of proteins; Ionic bridges; Reinforcement of ionic adsorption; Dextran-sulfate coated supports
First Page Preview
Use of polyvalent cations to improve the adsorption strength between adsorbed enzymes and supports coated with dextran sulfate
Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 39, Issue 2, 26 June 2006, Pages 332–336
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering