Institution: | a Laboratoire de Biochimie appliquée, I.U.T.A, University Claude Bernard-Lyon 1, 43 Boulevard du 11 Novembre 1918, 69622, Villeurbanne Cedex, France b LAGEP, University Claude Bernard-Lyon 1, UMR CNRS 5007, CPE Lyon, Bât. 308 G, 43 Boulevard du 11 Novembre 1918, 69622, Villeurbanne cedex, France c Department of Biochemistry and Genetics, Medical School, Newcastle upon Tyne NE2 4HH, UK |
Abstract: | Coupled interrelations occurring between a phosphatase/kinase reaction sequence acting in unstirred layers and on both sides of a charged biomembrane pore structure are presented as a plausible kinetic model for the primary active transport of phosphorylated molecules. Simulations conducted at the cell level and with credible numerical values demonstrate that the enzymes positions strongly regulate the membrane permeability for the transported substrate. Depending on both the enzymes positions (more or less far from the membrane) and the membrane charges, the membrane may appear either impervious, either permeable or able to actively transport a phosphorylated substrate. Globally all happens as if, in function of the enzymes positions, a permanent pore may be regulated, changing from a more closed to a more open conformation. |