2.5.1.21 2 (2E,6E)-farnesyl diphosphate - 2.5.1.21 2 (2E,6E)-farnesyl diphosphate first half-reaction 2.5.1.21 2 (2E,6E)-farnesyl diphosphate + NAD(P)H + H+ - 2.5.1.21 2 (2E,6E)-farnesyl diphosphate + NADPH + H+ - 2.5.1.21 2 (2E,6E)-farnesyl diphosphate + NADPH + H+ overall reaction 2.5.1.21 2 (2E,6E)-farnesyl diphosphate + NADPH + H+ squalene synthase catalyzes the first enzymatic step from the central isoprenoid pathway toward sterol and triterpenoid biosynthesis 2.5.1.21 2 (2E,6E)-farnesyl diphosphate + NADPH + H+ the enzyme catalyzes the first dedicated step in the biosynthesis of sterols and other triterpenoids 2.5.1.21 2 (2E,6E)-farnesyl diphosphate + NADPH + H+ the enzyme is involved in celastrol biosynthesis 2.5.1.21 2 farnesyl diphosphate - 2.5.1.21 2 farnesyl diphosphate + NADPH + H+ -