TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 CONT

According to the symmetry model, binding the first substrate molecule increases the tendency of the remaining subunits to undergo transition to the high-affinity form through an all-or-none effect, all subunits being either in their low-affinity or their high-affinity forms. The sequential model also postulates that the catalytic subunits have two conformational states, but it differs from the symmetry model in postulating that the subunits may undergo individual sequential changes in conformation; between the all-on and all-off states there may be many intermediate conformational states of the enzyme molecule, each having its own intrinsic catalytic activity.  1, fiche 1, Anglais, - high%2Daffinity%20form

Fiche 1,  Justifications,  Français

Record number: 1, Textual support number: 1 DEF

Forme active d'une enzyme allostérique qui fixe le substrat et l'activateur. Ces ligands stabilisent la molécule sous cette forme d'où l'effet coopératif. Par contre l'inhibiteur déplace l'équilibre vers la forme inactive. C'est-à-dire que, quand la concentration en substrat augmente, une augmentation sigmoïdale dans l'activité enzymatique peut apparaître.  2, fiche 1, Français, - forme%20%C3%A0%20haute%20affinit%C3%A9

Fiche 1,  Justifications,  Espagnol