title: The structural transitions of erythrocyte membranes induced by cyclic AMP.
abstract: The generalized structural transitions of erythrocyte membranes induced by cyclic AMP were registered by ESR, fluorescence, freeze-fracture and circular dichroism methods. Two transitions different in nature were revealed. One, which arises at 10-(11)--10-(10) M cyclic AMP, is cooperative and may be considered as a consequence of interaction of cyclic AMP with a receptor. It was calculated that a structural rearrangement in one erythrocyte ghost is induced by three cyclic AMP molecules. As a result of it the membranes are "loosened". The other transition arises at 10-(10)--10-(8) M cyclic AMP and depends on the activity of the protein kinase system. This transition was shown to be non-cooperative and due to phosphorylation of membranous proteins. During this rearrangement the membranes are "stiffened". Both transitions were demonstrated to relate to the membrane integrity.
mesh_terms: D002942:Circular Dichroism; D000242:Cyclic AMP / Q000008:administration & dosage / Q000494:pharmacology* / Q000502:physiology; D004578:Electron Spin Resonance Spectroscopy; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D004912:Erythrocytes / Q000648:ultrastructure*; D005614:Freeze Fracturing; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D013050:Spectrometry, Fluorescence
chemical_list: D008565:Membrane Proteins; D000242:Cyclic AMP