(''E'')-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP or HMB-PP) is an intermediate of the MEP pathway (non-mevalonate pathway) of isoprenoid biosynthesis. The enzyme HMB-PP synthase (GcpE, IspG) catalyzes the conversion of 2-''C''-methyl-D-erythritol 2,4-cyclodiphosphate (MEcPP) into HMB-PP. HMB-PP is then converted further to

isopentenyl pyrophosphate Isopentenyl pyrophosphate (IPP, isopentenyl diphosphate, or IDP) is an isoprenoid precursor. IPP is an intermediate in the classical, HMG-CoA reductase pathway (commonly called the mevalonate pathway) and in the ''non-mevalonate'' MEP pathway of i ...

(IPP) and

dimethylallyl pyrophosphate Dimethylallyl pyrophosphate (DMAPP; or alternatively, dimethylallyl diphosphate (DMADP); also isoprenyl pyrophosphate) is an isoprenoid precursor. It is a product of both the mevalonate pathway and the MEP pathway of isoprenoid precursor biosynt ...

(DMAPP) by

HMB-PP reductase 4-Hydroxy-3-methylbut-2-enyl diphosphate reductase (, ''isopentenyl-diphosphate:NADP+ oxidoreductase'', ''LytB'', ''(E)-4-hydroxy-3-methylbut-2-en-1-yl diphosphate reductase'', ''HMBPP reductase'', ''IspH'', ''LytB/IspH'') is an enzyme in the non- ...

(LytB, IspH). HMB-PP is an essential metabolite in most pathogenic bacteria including '' Mycobacterium tuberculosis'' as well as in

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

parasites, but is absent from the human host. HMB-PP is the physiological activator ("

phosphoantigen Non-peptidic antigens are low-molecular-weight compounds that stimulate human Vg9/Vd2 T cells, Vγ9/Vδ2 T cells. The most potent activator for Vγ9/Vδ2 T cells is (''E'')-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), a natural intermediate ...

") for human Vγ9/Vδ2 T cells, the major γδ T cell population in peripheral blood. With a bioactivity of 0.1 nM it is 10,000-10,000,000 times more potent than any other natural compound, such as IPP or alkyl amines. HMB-PP functions in this capacity by binding the B30.2 domain of BTN3A1.

References

External links

* {{DEFAULTSORT:Hydroxymethylbutenyl Pyrophosphate Biomolecules Metabolism Organophosphates Hemiterpenes