4 isopentenyl diphosphate + (2E,6E)-farnesyl diphosphate <=> all-trans-heptaprenyl diphosphate + 4 diphosphate
4 isopentenyl diphosphate + (2e,6e)-farnesyl diphosphate <=> all-trans-heptaprenyl diphosphate + 4 diphosphate