Binding selectivity is defined with respect to the binding of ligands to a substrate forming a complex. Binding selectivity describes how a ligand may bind more preferentially to one receptor than another. A selectivity coefficient is the equilibrium constant for the reaction of displacement by one ligand of another ligand in a complex with the substrate. Binding selectivity is of major importance in biochemistry and in chemical separation processes. The concept of selectivity is used to quantify the extent to which one chemical substance, A, binds each of two other chemical substances, B and C. The simplest case is where the complexes formed have 1:1 stoichiometry. Then, the two interactions may be characterized by equilibrium constants KAB and KAC. {A} + B AB; \mathit K_{AB}=\frac{[AB]}{[A][B]} {A} + C AC; \mathit K_{AC}=\frac{[AC]}{[A][C]} [X] represents the concentration of substance X (A, B, C, ...). A selectivity coefficient is defined as the ratio of the two equilibrium constants. This selectivity coefficient is in fact the equilibrium constant for the displacement reaction {AB} + C {AC} + B; \mathit K_{B,C}=\frac{[AC][B]}{[AB][C]} =\frac{\mathit K_{AC}[A][B][C]}{\mathit K_{AB}[A][B][C]} =\frac{\mathit K_{AC{\mathit K_{AB It is easy to show that the same definition applies to complexes of a different stoichiometry, ApBq and ApCq. The greater the selectivity coefficient, the more the ligand C will displace the ligand B from the complex formed with the substrate A. An alternative interpretation is that the greater the selectivity coefficient, the lower the concentration of C that is needed to displace B from AB. Selectivity coefficients are determined experimentally by measuring the two equilibrium constants, KAB and KAC. Receptor (biochemistry) In biochemistry the substrate is known as a receptor. A receptor is a protein molecule, embedded in either the plasma membrane or the cytoplasm of a cell, to which one or more specific kinds of signalling molecules may bind.

À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Graph Chatbot

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.