Reaction catalyzed by trifunctional (all-E)-isoprenyl diphospate synthase (2.5.1.B41), hexaprenyl diphosphate synthase [geranylgeranyl-diphosphate specific] (2.5.1.82)
+
2
=
2
+
geranylgeranyl diphosphate
+
2 isopentenyl diphosphate
=
2 diphosphate
+
all-trans-hexaprenyl diphosphate