Conformational change, energy-mediated

A number of transport mediators are transport proteins in the absence of an external energy supply, thermal motion leads to their conformational change or rotation so that the transported substance, bound at one side of the membrane, is transferred to the other side of the membrane. This type of mediator has a limited number of sites for binding the transported substance, so that an increase in the concentration of the latter leads to saturation. Here, the transport process is characterized by specificity for a given substance and inhibition by other transportable substances competing for binding sites and also by various inhibitors. When the concentrations of the transported substance are identical on both sides of the membrane,... 

Fig. 8. Schematic representation of protein-mediated cell adhesion on biomaterial surfaces. Biomaterial surface properties (such as hydrophilicity/hydrophobicity, topography, energy, and charge) affect subsequent interactions of adsorbed proteins these interactions include but are not limited to adsorbed protein type, concentration, and conformation. Changes in protein-surface interactions may alter accessibility of adhesive domains (such as the peptide sequence arginine-glycine-aspartic acid) to cells (such as osteoblasts, fibroblasts, or endothelial cells) and thus modulate cellular adhesion. (Adapted and redrawn from Schakenraad, 1996.)...

For example, with the Na+/K+ ATPase antiport the solute (Na+) binds to the carrier on one side of the membrane, an energy-mediated conformational change occurs involving phosphorylation of the protein via ATP and this allows the solute to be released on the other side of the membrane (figure 3,7). The... 

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