Dimethylallyl pyrophosphate (or -diphosphate) (DMAPP) is an intermediate product of both mevalonic acid

Mevalonic acid

Mevalonic acid is a key organic compound in biochemistry. The anion of mevalonic acid, the predominant form in biological media, is known as mevalonate. This compound is of major pharmaceutical importance...

 (MVA) pathway and DOXP/MEP pathway. It is an isomer of isopentenyl pyrophosphate

Isopentenyl pyrophosphate

Isopentenyl pyrophosphate is an intermediate in the classical, HMG-CoA reductase pathway used by organisms in the biosynthesis of terpenes and terpenoids. IPP is formed from acetyl-CoA via mevalonic acid...

 (IPP) and exists in virtually all life forms. The enzyme isopentenyl pyrophosphate isomerase catalyzes the isomerization of DMAPP from IPP.

Precursor of DMAPP in the MVA pathway is mevalonic acid, and 2-C-methyl-D-erythritol-e-P in the MEP/DOXP pathway.

At present, it is believed that there is crossover between the two pathways in organisms
that use both pathways to create terpene

Terpene

Terpenes are a large and diverse class of organic compounds, produced by a variety of plants, particularly conifers, though also by some insects such as termites or swallowtail butterflies, which emit terpenes from their osmeterium. They are often strong smelling and thus may have had a protective...

s and terpenoid

Terpenoid

The terpenoids , sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals similar to terpenes, derived from five-carbon isoprene units assembled and modified in thousands of ways. Most are multicyclic structures that differ from one another not only in...

s, such as in plants, and that DMAPP is the crossover product.