Trans-hexaprenyltranstransferase

In enzymology, a trans-hexaprenyltranstransferase is an enzyme that catalyzes the chemical reaction


 * all-trans-hexaprenyl diphosphate + isopentenyl diphosphate $$\rightleftharpoons$$ diphosphate + all-trans-heptaprenyl diphosphate

Thus, the two substrates of this enzyme are all-trans-hexaprenyl diphosphate and isopentenyl diphosphate, whereas its two products are diphosphate and all-trans-heptaprenyl diphosphate.

This enzyme belongs to the family of transferases, specifically those transferring aryl or alkyl groups other than methyl groups. The systematic name of this enzyme class is all-trans-hexaprenyl-diphosphate:isopentenyl-diphosphate hexaprenyltranstransferase. Other names in common use include all-trans-heptaprenyl-diphosphate synthase, heptaprenyl pyrophosphate synthase, heptaprenyl diphosphate synthase, and heptaprenyl pyrophosphate synthetase. This enzyme participates in biosynthesis of steroids.

Structural studies
As of late 2007, 11 structures have been solved for this class of enzymes, with PDB accession codes, , , , , , , , , , and.