hexaprenyl diphosphate synthase (geranylgeranyl-diphosphate specific) activity
hexaprenyl diphosphate synthase (geranylgeranyl-diphosphate specific) activity
Catalysis of the reaction: 2 isopentenyl diphosphate + (2E,6E,10E)-geranylgeranyl diphosphate = all-trans-hexaprenyl diphosphate + 2 diphosphate.