Notes: The COX (ovine/human) Inhibitor Screening Assay directly measures PGF2α by SnCl2 reduction of COX-derived PGH2 produced in the COX reaction. The prostanoid product is quantified via enzyme immunosorbent assay (ELISA) using an antiserum specific to PGF2α. This assay includes both ovine COX-1 and human recombinant COX-2 enzymes allowing the user to screen isozyme-specific inhibitors. This assay is an excellent tool which can be used for general inhibitor screening, or to eliminate false positive leads generated by less specific methods.