Farnesyl Diphosphate Farnesyltransferase 1 (FDFT1)

Farnesyl-diphosphate farnesyltransferase (FDFT1) is an enzyme that converts two units of farnesyl pyrophosphate into squalene.It has been described as the first dedicated enzyme of sterol (i.e., cholesterol, etc.) synthesis, since the squalene formed by it is exclusively routed into various sterols via a complex, multi-step pathway.Squalene synthase is considered to be an enzyme of eukaryotes or advanced organisms, although at least one prokaryote has been shown to possess a functionally similar enzyme.

In terms of structure and mechanics, squalene synthase most closely resembles phytoene syntase, which serves a similar role in many plants in the elaboration of phytoene, a precursor of many carotenoid compounds.