(E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate
chemical compound
(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 (IPP) and dimethylallyl pyrophosphate (DMAPP) by HMB-PP reductase (LytB, IspH).
Biochemical role
HMB-PP is an intermediate in the non-mevalonate pathway for the biosynthesis of the isoprenoid precursors isopentenyl pyrophosphate and dimethylallyl pyrophosphate. Most gram-negative bacteria, the photosynthetic cyanobacteria and green algae use only this pathway, while higher plants also use the mevalonate pathway.
The enzyme 4-hydroxy-3-methylbut-2-en-1-yl diphosphate synthase uses two reduced ferredoxin proteins per molecule of the precursor MEcPP to convert it to HMB-PP:
The final step in the non-mevalonate pathway is carried out by the enzyme 4-hydroxy-3-methylbut-2-enyl diphosphate reductase, which gives a mixture of dimethylallyl pyrophosphate and isopentenyl pyrophosphate in the ratio of five to one.
The products are then used in terpenoid biosynthesis.
HMB-PP is an essential metabolite in most pathogenic bacteria including Mycobacterium tuberculosis as well as in malaria parasites, but is absent from the human host.
HMB-PP is the physiological activator ("phosphoantigen") 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.
“(E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate” enters the record as chemical compound. Crown Archives preserves that source wording while asking what -4-Hydroxy-3-methyl-but-2-enyl, pyrophosphate and chemical can confirm, complicate or overturn.
Why this record matters
“(E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate” is worth following because a concise public description often conceals a longer documentary argument. Here, -4-Hydroxy-3-methyl-but-2-enyl, pyrophosphate and chemical provides the most credible route into that argument.
Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Jul 6, 2026. The linked authority identifier is Q2708007. None of the 0 selected statements returned an explicit reference.
A general summary may omit uncertainty, sample limits or methodological disagreement that is explicit in the technical record. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “(E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate”, its source revision and the description used here.
- Expand the search: follow (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate primary sources, (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate archive and -4-Hydroxy-3-methyl-but-2-enyl research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “(E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate”?
- Which observation, specimen, dataset or publication supports the account?
- Has classification or technical consensus changed since the cited source?
Search terms from this dossier
This entry incorporates text from “(E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.