title: Synthesis and use of 8-azidoguanosine 3',5'-cyclic monophosphate as photoaffinity label for cyclic GMP-dependent protein kinase.
abstract: 8-Azidoguanosine 3',5'-cyclic monophosphate (8-N3cGMP) has been synthesized for use as a photoactive probe for the labeling of cGMP receptors. The ability of 8-N3cGMP to be bound at specific cGMP binding sites was demonstrated by its ability to activate cGMP-dependent protein kinase isolated from bovine lung (Ka = 1.1 x 10(-7) M) and to inhibit competitively the binding of [3H] cGMP to the enzyme [Kd (8 N3GMP)/Kd (cGMP) = 6]. Photolysis of 8-N3[32P]cGMP in the presence of a crude enzyme preparation resulted in the covalent attachment of analog to cGMP-dependent protein kinase. Half-maximal labeling occurred at 2.2 x 10(-7) M. The incorporation of the analog was completely inhibited by the addition of cGMP.
mesh_terms: D000345:Affinity Labels; D000818:Animals; D001386:Azides; D002417:Cattle; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D004789:Enzyme Activation; D008168:Lung / Q000201:enzymology; D008970:Molecular Weight; D010777:Photochemistry; D011494:Protein Kinases / Q000378:metabolism*
chemical_list: D000345:Affinity Labels; D001386:Azides; D011494:Protein Kinases; D006152:Cyclic GMP