TERMIUM Plus^®

Fiche 1,  Justifications,  Anglais

Record number: 1, Textual support number: 1 CONT

Allosteric enzymes function through reversible, noncovalent binding of a regulatory metabolite called a modulator. They have other shapes or conformations induced by the binding of modulators. An example is feedback inhibition. An allosteric effect is described as a variation in proteins activity through the interaction of another molecule at a site on the protein which is distinct from the "active" site.(Ex. Hb and BPG.)  2, fiche 1, Anglais, - allosteric%20enzyme

Fiche 1,  Justifications,  Français

Record number: 1, Textual support number: 1 CONT

[...] les enzymes allostériques reconnaissent en s'y associant un substrat spécifique, et active sa conversion en produits. Mais en outre, ces enzymes ont la propriété de reconnaître électivement un ou plusieurs autres composés dont l'association (stéréospécifique) avec la protéine a pour effet de modifier, c'est-à-dire, selon le cas, d'accroître ou d'inhiber son activité à l'égard du substrat.  2, fiche 1, Français, - enzyme%20allost%C3%A9rique

Fiche 1,  Justifications,  Espagnol

Record number: 1, Textual support number: 1 OBS

Tradicionalmente, la Real Academia Española (RAE) admitía únicamente el género femenino para el sustantivo enzima; así fue hasta 1984, fecha en que pasó a considerarlo de género ambiguo, que puede funcionar por igual como masculino y como femenino. El uso, no obstante, parece haberse decantado claramente en español por el femenino, que hoy se emplea en el 90% de los casos [...]  2, fiche 1, Espagnol, - enzima%20alost%C3%A9rica

Fiche 2,  Justifications,  Anglais

Record number: 2, Textual support number: 1 CONT

Today nearly 2, 000 different enzymes are known. Many have been isolated in pure homogeneous form, and at least 200 have been crystallized.... NMR studies of globular proteins in solution give data consistent with the crystal structure, as has been amply demonstrated for lysozyme. However, where there is an equilibrium among two or more conformations of the enzyme in solution, crystallization may select out only one of the conformations. [alpha]-Chymotrypsin has a substantial fraction of an inactive conformation present under the conditions of crystallization, but only the active form of the enzyme crystallizes. An allosteric effector molecule that changes the conformation of the protein in solution may have no effect on the crystalline protein, as has been found, for example, with phosphorylase b. The enzyme is frozen in one conformation, with the crystal lattice forces preventing any conformational change. On the other hand, the addition of an effector to phosphorylase a causes the crystals first to crack and then to anneal, giving crystals of the enzyme in a second conformation.  2, fiche 2, Anglais, - crystallize

Fiche 2,  Justifications,  Français

Record number: 2, Textual support number: 1 DEF

Amener une substance à l'état de cristaux, lui donner la contexture régulière des cristaux.  1, fiche 2, Français, - cristalliser

Record number: 2, Textual support number: 1 CONT

Pour cristalliser une protéine, on place des échantillons en présence d'agents précipitants : solutions salines, solvants organiques ou polyéthylène glycol, dont on augmente progressivement la concentration par diffusion en phase gazeuse ou liquide. Pour les protéines membranaires, ces expériences se font en présence de détergents "doux". Comme la solubilité des protéines dépend du pH, de la température, de la présence d'ions métalliques ou de petites molécules qui se fixent sur la protéine, etc., des centaines de tests sont souvent nécessaires pour mettre au point une cristallisation.  2, fiche 2, Français, - cristalliser

Fiche 2,  Justifications,  Espagnol

Fiche 3,  Justifications,  Anglais

Record number: 3, Textual support number: 1 CONT

Triggered conformational changes ... are the motions of groups of atoms (i.e. individual side-chains) or whole sections of a protein (i.e. loops of chain, domains of secondary and tertiary structure, or subunit), which occur as a response to a specific stimulus. The distance moved can be as much as 10 [angstrom unit] or more. The time scale can be estimated by studies of the rate of binding or turnover reactions. The energy for triggered conformational change comes from specific interactions, such as electrostatic attractions or hydrogen bonding interactions. The best-known example of a triggered conformational change is the transition in tertiary structure that occurs when ligands bind to the iron atoms of hemoglobin.  1, fiche 3, Anglais, - triggered%20conformational%20change

Record number: 3, Textual support number: 1 OBS

The types of substances whose binding can trigger a specific conformational change include substrates(dihydroxyacetone phosphate in triose phosphate isomerase), coenzymes(NAD binding to lactate dehydrogenase), allosteric effectors(CTP and ATP in aspartic transcarbamylase), inhibitors(statine-containing polypeptide inhibitors of acid proteases) and even protons(the Bohr effect in hemoglobin; pH-dependent conformational changes in adenylate kinase).  1, fiche 3, Anglais, - triggered%20conformational%20change

Fiche 3,  Justifications,  Français

Record number: 3, Textual support number: 1 DEF

Modification de la conformation des protéines provoquée par la fixation de ligands à leur surface. Parmi ces ligands, notons les substrats, activateurs, inhibiteurs et coenzymes.  2, fiche 3, Français, - changement%20de%20conformation%20prot%C3%A9ique%20induit

Fiche 3,  Justifications,  Espagnol

Fiche 4,  Justifications,  Français

Fiche 4,  Justifications,  Espagnol