A photoaffinity label for the thromboxane A2/prostaglandin H2 receptor in human blood platelets.
A photoactive iodoarylazide derivative (I-APA-PhN3) of the competitive thromboxane A2/prostaglandin H2 (TXA2/PGH2) antagonist 13-azaprostanoic acid is evaluated. Upon photoactivation, the compound was found to inhibit specifically and irreversibly human platelet aggregation induced by the TXA2/PGH2 mimetic U46619. In receptor-binding studies using [3H]U46619, I-APA-PhN3 exhibited an IC50 of 300 nM for inhibition of U46619 binding. Photoactivation of I-APA-PhN3 resulted in an irreversible 58% reduction in specific binding of U46619. This compound and its corresponding ratio-iodinated form will prove to be useful tools for the isolation and purification of the TXA2/PGH2-binding protein in human platelets.
D000345:Affinity Labels / Q000378:metabolism*; D001241:Aspirin / Q000494:pharmacology; D001667:Binding, Competitive; D001792:Blood Platelets / Q000378:metabolism*; D006801:Humans; D010782:Photolysis; D010974:Platelet Aggregation; D011450:Prostaglandin Endoperoxides, Synthetic / Q000378:metabolism; D011466:Prostanoic Acids / Q000378:metabolism; D011982:Receptors, Prostaglandin / Q000378:metabolism*; D017482:Receptors, Thromboxane; D044244:Receptors, Thromboxane A2, Prostaglandin H2
D000345:Affinity Labels; D011450:Prostaglandin Endoperoxides, Synthetic; D011466:Prostanoic Acids; D011982:Receptors, Prostaglandin; D017482:Receptors, Thromboxane; D044244:Receptors, Thromboxane A2, Prostaglandin H2; C022574:13-azaprostanoic acid; D001241:Aspirin