IPPisomeraase

IPPisomerase, also known as isopentenyl diphosphate isomerase (IPPI), is an enzyme classified under the transferase class, specifically EC 5.3.3.2. It plays a crucial role in the biosynthesis of isoprenoids, a diverse group of compounds essential for various biological processes. Isoprenoids are found in all domains of life and include important molecules such as cholesterol, carotenoids, and rubber.

The enzyme catalyzes the isomerization of isopentenyl diphosphate (IPP) to dimethylallyl diphosphate (DMAPP), a reversible reaction that occurs in the mevalonate and methylerythritol phosphate (MEP) pathways. These pathways are the two primary routes for isoprenoid biosynthesis in organisms. In the MEP pathway, which is prevalent in bacteria, plants, and algae, IPPisomerase converts IPP to DMAPP, enabling the formation of prenyl diphosphates necessary for further isoprenoid synthesis.

Structurally, IPPisomerase is a homodimer, meaning it consists of two identical subunits. The active site of the enzyme facilitates the rearrangement of the double bond in IPP, converting it into DMAPP through a concerted mechanism involving proton transfers. This reaction is critical for the production of geranyl diphosphate, farnesyl diphosphate, and geranylgeranyl diphosphate, which serve as precursors for various secondary metabolites.

IPPisomerase has been extensively studied due to its role in the synthesis of pharmaceuticals, agrochemicals, and industrial chemicals. Inhibitors of this enzyme are potential targets for developing drugs to combat diseases such as malaria and cancer, as well as for controlling plant pathogens. The enzyme’s function has also been explored in metabolic engineering to enhance the production of valuable isoprenoids in biotechnological applications.