Isopentenyl-diphosphate delta isomerase (or isopentenyl pyrophosphate isomerase) (IPP isomerase) is an isomerase that catalyzes the conversion of the relatively un-reactive isopentenyl pyrophosphate (IPP) to the more-reactive electrophile dimethylallyl pyrophosphate (DMAPP). This isomerization is a key step in the biosynthesis of isoprenoids through the mevalonate pathway.
