title: A study of adenosine 3'-5' cyclic monophosphate binding sites of human erythrocyte membranes using 8-azidoadenosine 3'-5' cyclic monophosphate, a photoaffinity probe.
abstract: An earlier report (1a) has shown the utility of 8-N3cAMP (8-azidoadenosine-3', 5'-cyclic monophosphate) as a photoaffinity probe for cAMP binding sites in human erythrocyte membranes. The increased resolution obtained using a linear-gradient SDS polyacrylamide gel system now shows that: 1) both cAMP and 8-N3cAMP stimulate the phosphorylation by [gamma-32P]-ATP of the same red cell membrane proteins; 2) the protein of approximately 48,000 molecular weight whose phosphorylation by [gamma-32P]-ATP is stimulated by cAMP and 8-N3cAMP migrates at a slower rate than the protein in the same molecular weight range which is heavily photolabeled with [32P]-8-N3cAMP;3) other cyclic nucleotide binding sites exist besides those initially reported; 4) the variation in the ratio of incorporation of [32P]-8-N3cAMP into the two highest affinity binding sites appears to be the result of a specific proteolysis of the larger protein.
mesh_terms: D000345:Affinity Labels / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D008274:Magnesium / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism; D011953:Receptors, Cyclic AMP / Q000032:analysis* / Q000378:metabolism
chemical_list: D000345:Affinity Labels; D010710:Phosphates; D011953:Receptors, Cyclic AMP; D000242:Cyclic AMP; D006152:Cyclic GMP; D008274:Magnesium; D002118:Calcium