Xylulose 5-phosphate

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 470456055

| ImageFile = Xylulose 5-phosphate.svg

| ImageSize =

| IUPACName = 5-O-Phosphonato-D-xylulose

| OtherNames =

| SystematicName = {{sm|d}}-threo-Pent-2-ulose 5-phosphatehttps://iupac.qmul.ac.uk/2carb/

| Section1 = {{Chembox Identifiers

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C5H11O8P/c6-1-3(7)5(9)4(8)2-13-14(10,11)12/h4-6,8-9H,1-2H2,(H2,10,11,12)/p-2/t4-,5-/m1/s1

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = FNZLKVNUWIIPSJ-RFZPGFLSSA-L

| CASNo_Ref = {{cascite|changed|??}}

| CASNo = 60802-29-1

| PubChem = 850

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID=20015725

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEBI = 57737

| SMILES = [O-]P([O-])(=O)OC[C@@H](O)[C@H](O)C(=O)CO

| MeSHName = xylulose-5-phosphate

}}

| Section2 = {{Chembox Properties

| C=5 | H=11 | O=8 | P=1

| Appearance =

| Density =

| MeltingPt =

| BoilingPt =

}}

| Section3 = {{Chembox Hazards

| MainHazards =

| FlashPt =

| AutoignitionPt =

}}

}}

D-Xylulose 5-phosphate (D-xylulose-5-P) is an intermediate in the pentose phosphate pathway. It is a ketose sugar formed from ribulose-5-phosphate by ribulose-5-phosphate epimerase. In the non-oxidative branch of the pentose phosphate pathway, xylulose-5-phosphate acts as a donor of two-carbon ketone groups in transketolase reactions.{{cite journal |display-authors=6 |vauthors=Stincone A, Prigione A, Cramer T, Wamelink MM, Campbell K, Cheung E, Olin-Sandoval V, Grüning NM, Krüger A, Tauqeer Alam M, Keller MA, Breitenbach M, Brindle KM, Rabinowitz JD, Ralser M |date=August 2015 |title=The return of metabolism: biochemistry and physiology of the pentose phosphate pathway |journal=Biological Reviews of the Cambridge Philosophical Society |volume=90 |issue=3 |pages=927–963 |doi=10.1111/brv.12140 |pmc=4470864 |pmid=25243985 |doi-access=free}}

Xylulose-5-phosphate also plays a crucial role in the regulation of glycolysis through its interaction with the bifunctional enzyme PFK2/FBPase2. Specifically, it activates protein phosphatase, which then dephosphorylates PFK2/FBPase2. This inactivates the FBPase2 activity of the bifunctional enzyme and activates its PFK2 activity.{{Cite book |last=Nelson |first=David L. |title=Lehninger principles of biochemistry |last2=Cox |first2=Michael M. |last3=Nelson |first3=David L. |date=2013 |publisher=Macmillan Higher Education |isbn=978-1-4292-3414-6 |editor-last=Lehninger |editor-first=Albert L. |edition=6th |location=Basingstoke |pages=606}} As a result, the production of fructose 2,6-bisphosphate increases, ultimately leading to an upregulation of glycolysis.{{cite journal | vauthors = Uyeda K | title = Short- and Long-Term Adaptation to Altered Levels of Glucose: Fifty Years of Scientific Adventure | journal = Annual Review of Biochemistry | volume = 90 | issue = 1 | pages = 31–55 | date = June 2021 | pmid = 34153217 | doi = 10.1146/annurev-biochem-070820-125228 | doi-access = free }}

Although previously thought of mainly as an intermediary in the pentose phosphate pathway, recent research reported that the sugar also has a role in gene expression, mainly by promoting the ChREBP transcription factor in the well-fed state.{{cite journal | vauthors = Kabashima T, Kawaguchi T, Wadzinski BE, Uyeda K | title = Xylulose 5-phosphate mediates glucose-induced lipogenesis by xylulose 5-phosphate-activated protein phosphatase in rat liver | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 100 | issue = 9 | pages = 5107–5112 | date = April 2003 | pmid = 12684532 | pmc = 154306 | doi = 10.1073/pnas.0730817100 | doi-access = free | bibcode = 2003PNAS..100.5107K }}{{cite journal | vauthors = Iizuka K, Horikawa Y | title = ChREBP: a glucose-activated transcription factor involved in the development of metabolic syndrome | journal = Endocrine Journal | volume = 55 | issue = 4 | pages = 617–624 | date = August 2008 | pmid = 18490833 | doi = 10.1507/endocrj.k07e-110 | doi-access = free }} However, more recent study showed that D-glucose-6-phosphate, rather than D-xylulose-5-phosphate, is essential for the activation of ChREBP in response to glucose.{{cite journal | vauthors = Dentin R, Tomas-Cobos L, Foufelle F, Leopold J, Girard J, Postic C, Ferré P | title = Glucose 6-phosphate, rather than xylulose 5-phosphate, is required for the activation of ChREBP in response to glucose in the liver | journal = Journal of Hepatology | volume = 56 | issue = 1 | pages = 199–209 | date = January 2012 | pmid = 21835137 | doi = 10.1016/j.jhep.2011.07.019 }}