On the cooperativity of biological membranes.

Abstract : We extend the Monod-Wyman-Changeux of allosteric transitions in enzyme-substrate reactions to a membrane composed of identical units (protomers). It is supposed that each protomer can exist in two states. The interaction between protomers is treated in the molecular field approximation. It appears possible to have a first-order phase transition when the chemical potential of the substrate is varied, holding the temperature constant. The wide range of possible biological implications is discussed. (Author)