Reaction catalyzed by gamma-glutamylcyclotransferase (4.3.2.9)

		=			+
	D-gamma-glutamyl-O-[[(4-methyl-2-oxo-2H-1-benzopyran-7-yl)oxy]carbonyl]-L-serine	=		5-oxoproline	+		O-[[(4-methyl-2-oxo-2H-1-benzopyran-7-yl)oxy]carbonyl]-L-serine