ID 2.5.1.30 DE heptaprenyl diphosphate synthase. AN all-trans-heptaprenyl-diphosphate synthase. AN HepPP synthase. AN heptaprenyl pyrophosphate synthetase. AN trans-hexaprenyltranstransferase. CA (2E,6E)-farnesyl diphosphate + 4 isopentenyl diphosphate = all-trans- CA heptaprenyl diphosphate + 4 diphosphate. CC -!- This enzyme catalyzes the condensation reactions resulting in the CC formation of all-trans-heptaprenyl diphosphate, the isoprenoid side CC chain of ubiquinone-7 and menaquinone-7. CC -!- The enzyme adds four isopentenyl diphosphate molecules sequentially CC to farnesyl diphosphate with trans stereochemistry. DR P31112, HEPS1_BACSU; P55784, HEPS1_GEOSE; P31114, HEPS2_BACSU; DR P55785, HEPS2_GEOSE; //