Subcellular localization of binding sites for cytochalasin D: evidence from activation energies.
The activation energies for binding of tritiated cytochalasin D to HEp-2 cells and isolated plasma membrane were determined by Arrhenius plots. The higher value for intact cells (24 kcal/mol) compared to the plasma membrane fraction (4 kcal/mol at greater than 11.5 degrees C, 18 kcal/mol at less than 11.5 degrees C) was taken as evidence that [3H]cytochalasin D must penetrate the plasma membrane in order to reach its binding sites. The data support the conclusion that binding sites for [3H]cytochalasin D are intracellular, on the cytoplasmic face of the plasma membrane (rather than within the lipid bilayer), and on microsomes (endomembranes).
D001665:Binding Sites; D002151:Calorimetry; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003572:Cytochalasins / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism; D011485:Protein Binding; D011955:Receptors, Drug; D013696:Temperature; D013816:Thermodynamics
D003572:Cytochalasins; D009363:Neoplasm Proteins; D011955:Receptors, Drug