Reaction catalyzed by prostaglandin-E synthase (5.3.99.3)

		=
	(5Z,13E)-(15S)-9alpha,11alpha-epidioxy-15-hydroxyprosta-5,13-dienoate	=		(5Z,13E)-(15S)-11alpha,15-dihydroxy-9-oxoprosta-5,13-dienoate