title: High and low affinity sites associated with the binding of [3H]guanyl-5'-yl imidodiphosphate to liver plasma membranes.
abstract: Scatchard plots of the binding of [3H]Gpp(NH)p to rabbit and guinea pig liver plasma membranes were curvilinear, and could be resolved by computer-assisted non-linear regression analysis into two sites which exhibit high and low affinities. The two sites appear to be of equal capacities. The Kd values for binding to rabbit liver membranes were 5.6 +/- 0.5 nM and 133 +/- 20 nM for the high and low affinity sites, respectively. The Kd values for binding to similar sites on guinea pig liver membranes were 7.6 +/- 0.9 nM and 289 +/- 75 nM. In addition to Ns and Ni which have been identified in liver membranes, one or more of the other GTP-binding proteins may contribute to the observed binding.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D004492:Edetic Acid / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives*; D006165:Guanylyl Imidodiphosphate / Q000378:metabolism* / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D011869:Radioligand Assay
chemical_list: D006150:Guanine Nucleotides; D000266:Adenylyl Imidodiphosphate; D006165:Guanylyl Imidodiphosphate; D006160:Guanosine Triphosphate; D004492:Edetic Acid; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases