PGG2 is the first intermediate in the COX pathway which is stable enough to be isolated and characterized.{499} It is the C-15 hydroperoxide of PGH2. Under normal conditions, PGG2 is quickly metabolized by the peroxidase activity intrinsic to both COX-1 and -2 to give PGH2, which serves as the key precursor to the 2-series PGs and thromboxanes.{499,759}