Glutaraldehyde cross-linking of lipases adsorbed on aminated supports in the presence of detergents leads to improved performance.

Lipases from Candida rugosa (CRL) and lipase isoforms A and B from Candida antarctica (CAL-A and CAL-B) were adsorbed on aminated supports in the presence of detergents to have individual lipase molecules. Then, one fraction was washed to eliminate the detergent, and both preparations were treated with glutaraldehyde. The presence of detergent during the cross-linking of the lipases to the support permitted an increase in the recovered activity (in some instances, even by a 10-fold factor).

Stabilization of enzymes by multipoint attachment via reversible immobilization on phenylboronic activated supports.

In this work, we have used supports activated with m-amino-phenylboronic groups to "reversibly" immobilize proteins under very mild conditions. Most of the proteins contained in a crude extract from E. coli could be immobilized on Eupergit C-250 L activated with phenylboronic and then fully desorbed from the support by using mannitol or SDS.

Detection and purification of two antibody-antigen complexes via selective adsorption on lowly activated anion exchangers.

Taken advantage of the mechanism of adsorption of macro-molecules on ionic exchangers, (a multipoint interaction between the protein and the support), it is possible to selectively adsorb large proteins leaving small ones in the supernatant. Associated proteins should present a significant difference in its size as compared to the non-associated forms. Thus, the protein complexes may have much larger surfaces to interact with the support.

Selective and mild adsorption of large proteins on lowly activated immobilized metal ion affinity chromatography matrices. Purification of multimeric thermophilic enzymes overexpressed in Escherichia coli.

A strategy to selectively adsorb large proteins on immobilized metal ion affinity chromatography supports is presented. It is based on the fact that large proteins have a large surface that permits the long distance interaction with groups placed quite far apart (very dispersed onto the support surface) in the support, therefore, even using lowly activated supports, these proteins may be able to yield multiple interactions with the support, which is not possible for smaller proteins. This has been shown using a crude extract from Escherichia coli, where only large proteins were adsorbed on supports having 0.

Ion exchange using poorly activated supports, an easy way for purification of large proteins.

Ion-exchange chromatography using commercial ionic supports is a commonly used technique for protein purification. However, selective adsorption of a target protein from a given extract onto commercial ion exchangers seems to be quite complex since they are designed to adsorb the maximum percentage of proteins with the opposite charge. In this paper, ion-exchanger supports with different activation degrees (from 1 to 40 micromol of amino groups per g of agarose) have been prepared and used for the purification of large proteins.