Reaction catalyzed by heptaprenyl diphosphate synthase (2.5.1.30)

		+			=			+
	(2E,6E)-farnesyl diphosphate	+		3-propylbut-3-enyl diphosphate	=		diphosphate	+		(all-E)-3-propyl-7,11,15-trimethylhexadeca-2,6,10,14-tetraenyl diphosphate