Prostaglandin Endoperoxide H Synthases (Cyclooxygenases)-1 and −2

Abstract

Prostaglandin endoperoxide H synthases (PGHSs)1 catalyze the conversion of arachidonic acid and O2 to PGH2, the committed step in prostanoid biosynthesis (Fig. 1) (1). Before 1991, only one PGHS had been described, the isozyme now called PGHS-1, COX-1 (for cyclooxygenase-1) or the constitutive enzyme. At that time Simmons and Herschman and their colleagues discovered mRNAs whose expression was induced in chicken and mouse fibroblasts in response to src and tumor-promoting phorbol esters, respectively, and which encoded proteins having 60% amino acid sequence identity with PGHS-1.