Farnesyl-diphosphate farnesyltransferase

Squalene synthase (SQS ) (also farnesyl diphosphate farnesyl transferase, FDFT ) is the enzyme that catalyzes the condensation reaction of two molecules of farnesyl diphosphate to squalene, catalyzed in eukaryotes. This is a sub-step in the biosynthesis of cholesterol, and the first reaction, which only leads to cholesterol in animals. Is a transmembrane protein that is localized to the endoplasmic reticulum. SQS is a promising pharmacological target for lowering cholesterol levels.

There are homologous enzymes carotene -producing organisms, which condense as a partial step of the synthesis geranylgeranyl diphosphate ( GGPP ) to phytoene.

Catalyzed reaction

The reaction takes place in two partial steps:

2 ⇔ ⇔ PPi

First condense two molecules of farnesyl diphosphate to Präsqualendiphosphat.

2 NADPH / H ⇔ ⇔ 2 NADP PPi

Then Präsqualendiphosphat is reduced to squalene and rearranged.

Human Genome Organisation Digital Object Identifier
326707
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