FDFT1
Function
Catalyzes the condensation of 2 farnesyl pyrophosphate (FPP) moieties to form squalene. Proceeds in two distinct steps. In the first half-reaction, two molecules of FPP react to form the stable presqualene diphosphate intermediate (PSQPP), with concomitant release of a proton and a molecule of inorganic diphosphate. In the second half-reaction, PSQPP undergoes heterolysis, isomerization, and reduction with NADPH or NADH to form squalene. It is the first committed enzyme of the sterol biosynthesis pathway.
Involvement in disease
Squalene synthase deficiency
SQSD
An autosomal recessive disorder characterized by profound developmental delay, brain abnormalities, 2/3 syndactyly of the toes, facial dysmorphisms, low total and LDL-cholesterol, and abnormal urine organic acids.
None
The disease is caused by variants affecting the gene represented in this entry.
Pathway
Terpene metabolism; lanosterol biosynthesis; lanosterol from farnesyl diphosphate: step 1/3.
Sequence Similarities
Belongs to the phytoene/squalene synthase family.
Tissue Specificity
Widely expressed.
Cellular localization
- Endoplasmic reticulum membrane
- Multi-pass membrane protein
Alternative names
Squalene synthase, SQS, SS, FPP:FPP farnesyltransferase, Farnesyl-diphosphate farnesyltransferase, Farnesyl-diphosphate farnesyltransferase 1, FDFT1