5.3.3.2	physiological function	involved in terpenoid metabolism	
5.3.3.2	metabolism	IPP isomerase activity is a rate-limiting step in terpenoid synthesis	
5.3.3.2	physiological function	isopentenyl diphosphate and dimethylallyl diphosphate are essential precursors for terpenoid biosynthesis	
5.3.3.2	metabolism	the enzyme plays a critical role in terpenoid metabolic pathways	
5.3.3.2	metabolism	the plastidial enzyme plays an important function in carotenoid biosynthesis