Farnesyl-diphosphate farnesyltransferase

Farnesyl-diphosphate farnesyltransferase (or squalene synthase) is an enzyme which converts farnesyl pyrophosphate into squalene.



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.

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.

Mechanistically and structurally, 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. (Carotenoids are the colorful pigments present in most vegetables.)

Inhibition of squalene synthase, e.g. by lapaquistat, is under investigation as a method of lowering cholesterol levels in the prevention of cardiovascular disease.