TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 DEF

Method based on the covalent attachment of enzymes to water insoluble matrices. It is the most widespread and one of the most investigated approaches to enzyme immobilisation. The selection of conditions for immobilization is more difficult than in the cases of the other carrier binding methods described, and frequently involves more complicated and less mild conditions than the other methods, but, since covalent bonds are being formed, stable immobilized enzyme preparations which do not leach enzyme into solution in the presence of substrate or high ionic concentration solutions are formed in almost all cases. The immobilization of an enzyme by covalent attachment to a support matrix must involve only functional groups of the enzyme that are not essential for catalytic action, and therefore no reagents must be used which could affect the binding and active sites of the enzyme.  2, fiche 1, Anglais, - covalent%20binding

Record number: 1, Textual support number: 1 CONT

The reaction conditions required for covalent binding are relatively complicated and not particularly mild. Therefore, in some cases, covalent binding alters the conformational structure and active center of the enzyme, resulting in major loss of activity and/or changes of substrate specificity.  3, fiche 1, Anglais, - covalent%20binding

Fiche 1,  Justifications,  Français

Record number: 1, Textual support number: 1 DEF

Technique largement employée dans le cas des enzymes qui met en jeu une réaction chimique créant une liaison irréversible entre la molécule enzymatique et les groupes réactifs du support. A ce type de liaison se surajoutent toujours des phénomènes d'adsorption électrostatique qui consolident la fixation.  2, fiche 1, Français, - fixation%20par%20liaison%20covalente

Record number: 1, Textual support number: 1 CONT

L'enzyme fixée à un support soluble ou insoluble peut très facilement être récupérée en fin de réaction et être réemployé plusieurs fois et même fonctionner en continu dans des réacteurs. Il existe trois grands types d'immobilisation des enzymes : l'inclusion, l'adsorption et la fixation par liaison covalente.  3, fiche 1, Français, - fixation%20par%20liaison%20covalente

Fiche 1,  Justifications,  Espagnol