Prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase), also known as PTGS2, is a protein which in humans is encoded by the PTGS2 gene. Prostaglandin-endoperoxide synthase (PTGS), also known as cyclooxygenase, is the key enzyme in biosynthesis of the prostanoids, (prostaglandins, prostacyclin and thromboxanes.) It acts both as a dioxygenase and as a peroxidase. There are two isozymes of PTGS: a constitutive PTGS1 and an inducible PTGS2, which differ in their regul… (More on Cox-2)