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+	-	
2.5.1.21	farnesyl diphosphate + farnesyl diphosphate	-	
2.5.1.21	farnesyl diphosphate + farnesyl diphosphate	first pathway-specific enzyme in cholesterol biosynthesis	
2.5.1.21	farnesyl diphosphate + farnesyl diphosphate	squalene is the first sterol intermediate in cholesterol biosynthesis	
2.5.1.21	farnesyl diphosphate + farnesyl diphosphate	essential enzyme in cholesterol biosynthetic pathway	
2.5.1.21	farnesyl diphosphate + farnesyl diphosphate	enzyme may be important during response to infection and inflammation	
2.5.1.21	additional information	enzyme is key regulator not only for phytosterol but also for triterpene biosynthesis	
2.5.1.21	additional information	the catalytic process involves two reactions: firstly, two FPP molecules are condensed to form presqualene diphosphate (PSPP), an intermediate with a cyclopropane C1'-C2-C3 ring structure, and secondly, PSPP undergoes a NADPH-dependent rearrangement and reduction to generate the end product squalene	
2.5.1.21	additional information	squalene and botryococcene are branched-chain, triterpene compounds that arise from the head-to-head condensation of two molecules of farnesyl diphosphate to yield 1'-1 and 1'-3 linkages, respectively. Different enzymes are responsible for botryococcene and squalene biosynthesis in the green alga Botryococcus braunii race B. The specificity for the 1'-1 and 1'-3 linkages is controlled by residues in the active sites that can mediate catalytic specificity. Identification of several amino acid positions contributing to the rearrangement of the cyclopropyl intermediate to squalene, The same positions do not appear to be sufficient to account for the cyclopropyl rearrangement to give botryococcene, oerview	
2.5.1.21	presqualene diphosphate + NAD(P)H + H+	-	
2.5.1.21	presqualene diphosphate + NADPH + H+	-	
2.5.1.21	presqualene diphosphate + NADPH + H+	second half reaction