A cytochrome P450 monooxygenase that catalyzes the omega-hydroxylation of prostaglandin E2. Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (CPR; NADPH-ferrihemoprotein reductase). O2 + prostaglandin E2 + reduced [NADPH--hemoprotein reductase] = 20-hydroxy prostaglandin E2 + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] Belongs to the cytochrome P450 family.