title: Interaction of adenosine and adenylnucleotides with the human platelet membrane. Further characterization of the ADP binding sites.
abstract: The binding of adenosine and adenylnucleotides to the human platelet membrane has been measured and the subsequent effect on the binding of 14C-ADP has been determined. The following conclusions have been drawn: (1) Two reactions with different velocities (t 1/2 = 15--30 sec and t 1/2 = 4--6 min) seem to be involved in the binding of ADP to the platelet membrane. (2) AMP binds to the platelet membrane and partially inhibits binding of ADP in a competitive manner. These two findings suggest that ADP binding sites on the platelet membrane may be of more than one type. (3) At concentrations up to 10(-5) M, ATP does not itself bind to the platelet membrane but is rapidly transformed into ADP which, in turn, binds to the membrane and inhibits the binding of 14C-ADP. (4) Adenosine does not significantly interfere with the binding of 14C-ADP and has not been shown to bind to the platelet membrane.
mesh_terms: D000241:Adenosine / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D001665:Binding Sites; D001667:Binding, Competitive; D001792:Blood Platelets / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002462:Cell Membrane / Q000378:metabolism; D006801:Humans; D007700:Kinetics
chemical_list: D002250:Carbon Radioisotopes; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000241:Adenosine